MacMen mentioned a problem with stuck custom OSD Elements in the betaflight git issues: Github
I have the same Problem, and cause it seems only DJI users have this problem I think mostlikely its an DJI custom OSD Problem.

-After some time not all OSD Elements get updated every Second.
-GPS coordinates work fine
-used mAh and actual Current for Example get stuck
-used mAh for example jumped from around 600mAh to 1400mAh with no update in between

Update from the Github thread:
-in the blackbox log of the Flight controller the data ist consistent- just the goggles or the airunit don`t get updated with the actual Value
-the max7456_spi_bus = 0 is generaly no longer needet with 4.1.3 but it seems thats it is unrelated to this OSD Stuck Problem

hope you can inspect the Problem and give us some feedback.

Greets
downset

MacMen here, i have the same issue. I use T-Motor F7 HD Flight Controller and the FC dont have onboard OSD Chip. Correspond to this Thread i have changed the default "max7456_spi_bus = 2" to max7456_spi_bus = 0"

https://forum.dji.com/forum.php?mod=viewthread&tid=203712&page=1#pid2030924

I will try this again and report the results here.

@MacMen do you have "Automatic Temp control" setting in the goggles on or off?

just another guess but maybe it is related to that.
I have it on, next flight i will set it off for a test, but the weather is so bad the next days - maybe you get quicker in the air.

I`m wondering that so less people complaining about it so maybe it is a setting nobody uses.
Cause it happens after some flight time, and not sure but I think on the second battery Pack faster than on first maybe it is related to heat / power saving features.

downset Posted at 2-2 00:57
@MacMen do you have "Automatic Temp control" setting in the goggles on or off?

just another guess but maybe it is related to that.

got a dry moment to fly 3 packs today
same stuttering osd also with "temp control" off so forget my thoughts  about that

There are not many settings =O)

I have Temp control active (ON). And nothing but rain outside....

I have this issue too. It doesn’t always happen. It seems more likely to happen after a throttle punch.

Tom_A Posted at 2-4 18:21
I have this issue too. It doesn’t always happen. It seems more likely to happen after a throttle punch.

That i can not confirm. I have this Issue also with LiIon Akku where you can not punch the throttle. Tomorrow i hope for better Wether.

I have setup my Radio Telemetry Sensors to my Display. So at the next test I can compare the OSD information when it starts to stutter and the original Telemetry Data on the Radio. Than we have more Information.
What have i changed at the moment from start of this issue to now.

-Add a capacicator 100nF between Current sens and GND to the FC. And i have set the Current Offset in Betaflight from -5100 back to 0.

-max7456_spi_bus = 2 (is at default)

-I have changed the Gyro update frequency and PID loop frequency to 8k/8k

Today i have flown 4x 1550mAh Packs and the Issue dose not show up!

Today i have flown another 2 Packs and the OSD Elements are stuttering again. Nothing changed!!!

These Elements updating fine:
GSP Latitude and Longitude
GPS Number of Sats
RSSI
DJI Channel + Signal strength
DJI Recording Time for Copter and Goggles

These Ellements are stuttering:
Battery Cellvoltage
Used mAh
Actual Current usage
Battery Voltage
Is nobody interested in fixing the problem (DJI)????

I have noticed that same issue too a few times already.

Same problem here, in both my quads.
But Only if I have a memory card in the Air-unit and record.
Maybe this can provide a clue to the designers...

Same problem for me since I updated to 1.00.04.
With previous firmware I did not have that issue.
And I am also using a T-Motor F4 with 55 ESC.
I also had the impression that it appeared more often after a punch.
But not always. And it has nothing to do with distance away from pilot.
I was flying next to me and it did not update OSD.
Interestingwise It did not happen when I was using a 4s battery.
Eventhough I was going full throttle for a second.

I have set the Amperage Meter / Battery / Scale to 249 and this is very accurate.
But only with some batteries.
With other it's like 20-30% away from what I am charging after the flight.
Anyone knows why?
Why are you using the mA offset?

Thanks DJI for solving this problem :-)

cmmoser Posted at 2-17 06:26
Same problem for me since I updated to 1.00.04.
With previous firmware I did not have that issue.
And I am also using a T-Motor F4 with 55 ESC.

I was using the mA offset to get the correct numbers. I was measure external current with an Amp- Meter and compared to the Betaflight Value. So i have to enter a Offset of -5100 to match the Numbers.
Now i have put a 100nF between Current SENS and GND to the FC and i get close values with mA offset = 0.

Stuttering OSD:
I have the Issue with 6S and 4S. Next time i will  fly some Packs without a SD Card on the Air Unit. Only to check if it´s better or not.

Today a flew 6 packs 3 with SD Card in the Air Unit and 3 without SD. With recording during flight the OSD elements are stuttering again. Without recording (no SD in Air Unit) no problems OSD is working fine! So this is the workaround until DJI will fix this issue. OR you buy a Caddx Vista without onboard recording. Than you save money, weight and you have a working OSD!

Using BTFL 4.1.4, Target: HBRO/KAKUTEF7HDV(STM32F745) and the latest DJI Firmware my amp meter and usage data somehow get stuck around 500mah used, sometimes the values continue, sometimes they don`t . Also looks that if the count continues the refresh rate is stuttering

Can confirm I have this issue on all firmwares since .200. Does it on three different air units one of them brand new. 3s 4s 6s all the same. 3" 5" 6" 7" props. Yes I do notice it does it sometimes after punching out but could just be a coincidence. Even when flying efficiently for a long 7 minute flight it will just stop for a while which when you are near the end of your flight can mean you don't know if you are under or over your mAh safety limit. Seems like it should be a really easy fix for DJI.
I still think hardcoded OSD elements would be fine if they kept them within the focus mode area if DJI are looking to explore alternatives.

There is a closed issue for Betaflight 4.2 that looks like the issue may be with Betaflight. If that is the case, the issue will be fixed by upgrading to Betaflight 4.2, when it is available.

I have this problem as well and I believe it's not betaflight issue. I'm on the latest betaflight to this date and it's happening to me. And as someone already mentioned, it's happening only when recording to air unit memory card. Otherwise it's okay. So air unit recording is somewhat unusable now.

I'm glad I found this.  I had the same issue on the last 5 packs i flew and didn't know why.  Then it dawned on me I had started using an SD card on those flights.  I hope they fix this soon.  What's the point of having onboard recording if your battery voltage freezes.  I almost lost the quad one flight cause didn't notice it froze so no low voltage warning!

Hacky4 Posted at 3-14 14:01
I have this problem as well and I believe it's not betaflight issue. I'm on the latest betaflight to this date and it's happening to me. And as someone already mentioned, it's happening only when recording to air unit memory card. Otherwise it's okay. So air unit recording is somewhat unusable now.

The github issue was for a not yet released version. Are you running a beta version of Betaflight. It's 4.2 that should have the fix. I believe I have seen this issue without recording. There multiple issues causing lag. Look at the 4.2 release issues and you will see one related to the type of communication being used for the OSD data.

Stevo11 Posted at 3-16 18:35
I'm glad I found this.  I had the same issue on the last 5 packs i flew and didn't know why.  Then it dawned on me I had started using an SD card on those flights.  I hope they fix this soon.  What's the point of having onboard recording if your battery voltage freezes.  I almost lost the quad one flight cause didn't notice it froze so no low voltage warning!

I'll have to do more testing with recording. Sometimes I do not bother to record because I have a GoPro mounted. I run a ViFly buzzer on the quads I built. It's extremely loud. You can't use motor buzzer for low voltage. I'd reccomend installing a buzzer. The ViFly has the advantage of having its own battery so it can work even if the quads battery comes unplugged. Extremely loud. If you get in the habit of flying closer as the battery gets lower, you can definitely hear it if you OSD fails to update.

Tom_A Posted at 3-16 18:58
The github issue was for a not yet released version. Are you running a beta version of Betaflight. It's 4.2 that should have the fix. I believe I have seen this issue without recording. There multiple issues causing lag. Look at the 4.2 release issues and you will see one related to the type of communication being used for the OSD data.

I'm not running beta. I did not catch, you are talking about beta version. Anyway, could you please share the issue URL or the issue number?

I still believe it is due to air unit recording. I've encountered the issue and it disappeared as soon as I disabled air unit recording - it seems to be confirmed by others as well.

Hacky4 Posted at 3-17 01:54
I'm not running beta. I did not catch, you are talking about beta version. Anyway, could you please share the issue URL or the issue number?

I still believe it is due to air unit recording. I've encountered the issue and it disappeared as soon as I disabled air unit recording - it seems to be confirmed by others as well.

I think this is the issue:
https://github.com/betaflight/betaflight/pull/9013

I am thinking that the laggy OSD could be more than one issue with similar symptoms. I don't feel right running a beta version of Betaflight so will need to wait to see how much this fix helps. Hopefully if there is an issue with recording and the OSD, DJI catches that on the next update as well.

One of my flight controllers has bluetooth to connect to the SpeedyBee app. Bluetooth was mentioned in the closed PR, but I'm not sure if it affects that one or not. I do know that both my 5" quad's controllers have the PID loop timing issue if I don't turn off sending OSD data to the OSD chip although it was only supposed to be a problem if the board did not have the chip.

Hacky4 Posted at 3-17 01:54
I'm not running beta. I did not catch, you are talking about beta version. Anyway, could you please share the issue URL or the issue number?

I still believe it is due to air unit recording. I've encountered the issue and it disappeared as soon as I disabled air unit recording - it seems to be confirmed by others as well.

I did two flights just now with a Kopis Cinewhoop recording on the Air unit. The first time I flew seemed like it might have been less laggy on the OSD. That flight was on low latency with focus mode. The second flight was high quality and focus mode auto. I noticed at one point the OSD didn't update for a little while but eventually did. Are you sure you never have laggy OSD when not recording on the Air unit? It seems a bit unpredictable as to when it is going to happen.

Tom_A Posted at 3-16 19:03
I'll have to do more testing with recording. Sometimes I do not bother to record because I have a GoPro mounted. I run a ViFly buzzer on the quads I built. It's extremely loud. You can't use motor buzzer for low voltage. I'd reccomend installing a buzzer. The ViFly has the advantage of having its own battery so it can work even if the quads battery comes unplugged. Extremely loud. If you get in the habit of flying closer as the battery gets lower, you can definitely hear it if you OSD fails to update.

Thanks Tom! I'll pick one of those up as a backup if i lose the thing.  I didn't know about it.

I flew some packs today and got a little more info on the OSD freezing.  Mine also freezes during punchout.  And then updates sporadically after.
I changed my video to low latency and then that allowed me to change the recordings to 720p.  That flight had no OSD issues.  When I went back to 1080p video and best quality settings then the issue returned.  
The next thing i want to try is if you manually stop recording does the OSD start working again?  Maybe the solution is just record when you want to and not all the time like i was hoping to do.

Stevo11 Posted at 3-18 16:37
I flew some packs today and got a little more info on the OSD freezing.  Mine also freezes during punchout.  And then updates sporadically after.
I changed my video to low latency and then that allowed me to change the recordings to 720p.  That flight had no OSD issues.  When I went back to 1080p video and best quality settings then the issue returned.  
The next thing i want to try is if you manually stop recording does the OSD start working again?  Maybe the solution is just record when you want to and not all the time like i was hoping to do.

If you are right about this, I don't think only recording when you want to record is a good solution. Recording starts and stops on both the air unit and goggles at the same time if you have them set to both record. You are going to want the goggles to record all the time in case something goes wrong. You might need to watch the last bit of footage to find the quad if it goes down.
Toggling recording on and off though might be a good work-around if it does work.

Stevo11 Posted at 3-18 16:37
I flew some packs today and got a little more info on the OSD freezing.  Mine also freezes during punchout.  And then updates sporadically after.
I changed my video to low latency and then that allowed me to change the recordings to 720p.  That flight had no OSD issues.  When I went back to 1080p video and best quality settings then the issue returned.  
The next thing i want to try is if you manually stop recording does the OSD start working again?  Maybe the solution is just record when you want to and not all the time like i was hoping to do.

Did you record on both goggles and air unit? Did you try recording only to goggles?

That's a good point.  Would def want to be recording if the quad goes down.
I have been recording on both goggles and air unit for my testing.

Stevo11 Posted at 3-20 11:34
That's a good point.  Would def want to be recording if the quad goes down.
I have been recording on both goggles and air unit for my testing.

Record just on goggles. I did not experience OSD lag when recording just on goggles. I did however experience massive lag when recording on both goggles and air unit. So massive it practically stopped updating and I did not know the voltage, so I setup my buzzer on low voltage just for sure.

Just tested Betaflight 4.1.5 and it seems to update the OSD more frequently. Not sure this fixes the OSD completely freezing at times, but did fly while recording to the air unit. No throttle punches though. When I have had the OSD completely stop refreshing it has usually been on a throttle punch.

Tom_A Posted at 3-22 12:28
Just tested Betaflight 4.1.5 and it seems to update the OSD more frequently. Not sure this fixes the OSD completely freezing at times, but did fly while recording to the air unit. No throttle punches though. When I have had the OSD completely stop refreshing it has usually been on a throttle punch.

I was flying many packs without recording on air unit now and did not experience OSD lag once. At least cell voltage and RX rssi worked flawlessly. I'm more and more confident air unit recording causes the issues. At least in my case.

I will try recording to air unit on my next few packs, just to see whether the issue comes back again. I've lost my MicroSD in one of my last crashes though, so I have to get a new one first.

Hacky4 Posted at 3-22 14:57
I was flying many packs without recording on air unit now and did not experience OSD lag once. At least cell voltage and RX rssi worked flawlessly. I'm more and more confident air unit recording causes the issues. At least in my case.

I will try recording to air unit on my next few packs, just to see whether the issue comes back again. I've lost my MicroSD in one of my last crashes though, so I have to get a new one first.

I did some more flights on Betaflight 4.1.5. Although it resolved some consistent lag issues, I do notice now that there is another lag issue that is intermittent that seems to be related to on board recording.

Downgrade firmware to v01.00.02.  Haven't seen the issue on 02.  Don't think its anything to do with BF.

I also found out if you land. Disarm and rearm it fixes it every time for me. The osd starts updating like normal again

Stevo11 Posted at 4-3 01:51
I also found out if you land. Disarm and rearm it fixes it every time for me. The osd starts updating like normal again

If you are using the DJI remote, you might try turning recording off and then on while flying. If this issue is related to recording on the air unit, disarming may be fixing the issue because that also stops recording. I will give this a test when I get a chance. I have GoPro mounts on everything now, so I usually do not bother with recording on the air unit any more.

Hacky4 Posted at 3-22 14:57
I was flying many packs without recording on air unit now and did not experience OSD lag once. At least cell voltage and RX rssi worked flawlessly. I'm more and more confident air unit recording causes the issues. At least in my case.

I will try recording to air unit on my next few packs, just to see whether the issue comes back again. I've lost my MicroSD in one of my last crashes though, so I have to get a new one first.

Thanks for the tip. I will try it.
Bye the way: Did anyone notice a difference between TELEMETRY on/off?

Greetings Fabi

It definitely is NOT a betaflight issue - I am running kiss and am having the same problem, happens every 6 packs or so (froze all the osd elements, mah, voltage, amps) ... Felt safe after it didn't happen for 5 packs and 5 minutes later I ran to the charger to nurture a battery from 11 volts back up... Always had an sd card in the air unit (which is gonna be removed for sure if that fixes the issue, gonna test that soon)

CopterTec Posted at 4-8 11:37
Thanks for the tip. I will try it.
Bye the way: Did anyone notice a difference between TELEMETRY on/off?

I'm not using DJI controller, so I'm not using DJI for RX and therefor I believe CRSF telemetry should not affect this, because it should be sent just from the FC to the CRSF.

Anyway, with lagging OSD I'm definitely not giving away my telemetry as it is the only reliable way to get low voltage reading and land safely for me.

By the way, I'm now almost totally sure it's due to recording in the air unit. I tried to use slow microSD and stuttering was even more apparent - it even completely stopped updating until I rearmed again. With fast microSD it is "just" lagging.

Update from my side:
1) Air Unit with SD card and recording on = OSD hangs most of the time
2) Air Unit with SD card and recording off = OSD works but sometimes slow
3) Air Unit without SD card = very smooth and great OSD

Notice: Goggles with/without SD card and/or recording on/off = no difference

So I think that the SD card is the problem (what Hacky4 said). The OSD is only fine without SD card.