Has any forum user confirmed in person that this 256 GB card actually works ok with the Action 3 in real world use?  I chatted with Support today and they could only confirm that it was on the approved list.  They had no personal knowledge if it worked or not.  
The Kingston 256 GB React is not even made in a Micro SD - in Canada or the USA.  So Support confirmed this needs to be revised and corrected in all DJI documentation.  

Hello there 10-Bit. Good day and thank you for reaching out. Kindly please refer to the post below for additional reference on this matter.

Please note that:
1. The DJI Osmo Action 3 supports microSD card with a storage of up to 256G.
2. MIcroSD card models that have been tested to be incompatible are as follows:
1) SanDisk Extreme Pro 64GB UHS-I Speed Grade 3 microSDXC
2) SanDisk Extreme Pro 128GB UHS-I Speed Grade 3 microSDXC
When using the DJI Osmo Action 3 with cards that are not included in the compatibility list or have been tested to be incompatible, it is probable that the recording may stop automatically. Therefore, it is not recommended to use these cards. It is OK if you would like to use them to record videos with a low resolution or low frame rate, but we do not guarantee the security of the footage you captured.

Thank you.

It is pretty funny that Pocket 2 DO NOT work with Kingston Cards and now for Action 3 those are recommended.

Srly?

Been using SanDisk Extreme Pro 64GB UHS-I Speed Grade 3 microSDXC with Pocket 2 (since its launch) and Action 2 a bit without any problem... how come it was tested to be incompatible with the latest Action 3?
The  SanDisk Extreme Pro are some of the best SD cards on the market. The action 3 should be made compatible with them instead of the contrary.

Aavalaakso Posted at 9-17 03:59
It is pretty funny that Pocket 2 DO NOT work with Kingston Cards and now for Action 3 those are recommended.

Srly?

I use Kingston in my Pocket 2 and never had any problems with it.

johansenfoto Posted at 9-18 01:27
I use Kingston in my Pocket 2 and never had any problems with it.

I have 7 different Kingston cards and all of those stops recording after longer 4k recording without saying anything. I sent P2 back to the DJI and another Pocket 2 I received for warranty did exactly the same thing. Something like 10-20 minutes and it stops recording without saying anything.

With Samsung Cards I can record 1-2 hours without any problems. (All my Kingston cards works with Pocket 1 flawlessly.

I reported this to DJI and they only said that use Samsung Cards.

I just have feelings they have some different hardware in same Pocket models. They even changed lens color once with Pocket 1. So they have some hardware that rejects Kingston.

Been IT professional decades and I have other topic about Kingston Cards somewhere here in the forums.

Could be that your cards is not fast enough and/or fake cards bought from amazon/ebay.

johansenfoto Posted at 9-18 12:50
Could be that your cards is not fast enough and/or fake cards bought from amazon/ebay.

Today I tested the SAMSUNG PRO Plus 256 GB U3 A2 V30:
No problems in formatting!

More tests in next days.

johansenfoto Posted at 9-18 12:50
Could be that your cards is not fast enough and/or fake cards bought from amazon/ebay.

Like your sarcasm.

Sure we who manage University Server Clustering and run Virtual Servers we definitely buy everything from eBay.

Despite of that I'm not fan of Samsung at all still use Samsung cards to be sure since there are many Pocket 2 devices that do not work using Kingston U3 A2 cards sent by Kingston for me.

djiuser_zEKgdWRops1S Posted at 9-19 01:25
Today I tested the SAMSUNG PRO Plus 256 GB U3 A2 V30:
No problems in formatting!

That works fine. All my Samsung cards works with Pocket 2 without any errors.

djiuser_zEKgdWRops1S Posted at 9-19 01:25
Today I tested the SAMSUNG PRO Plus 256 GB U3 A2 V30:
No problems in formatting!

Nice!

If you can confirm that it records 4Kp60 HB - 4Kp120 RS - 4Kp60 4:3 RS - 2.7Kp60 HS - 2.7Kp120 RS - 2.7Kp60 4:3 RS without any issues - that would be very much appreciated.  I ordered the Samsung 256 and OA3 a few days ago to replace my lost OA2 - but unfortunately will not be able to use and test until mid-October.

Looking forward to having 2 replaceable batteries at the ready.  Since almost every use - ran out of battery using the OA2 while I had it.  Nice small device - but had specific limitations.  OA3 looks to have most all those limitations corrected - which is very positive.

Finally if you have an external mic you use - can you confirm that there is some sort of gain control to "reduce" sound input.  My Saramonic UC Mini is great to increase volume as it runs hot - but is unusable in very windy situations mounted outside like boating - sailing - driving - biking down steep hills.  It clips badly making the audio unusable.  I thought some video showed 3 volume settings now.

Hopefully the new OA3 onboard wind panel will help as per some review videos - as the OA2 wind reduction setting was not that effective in most windy situations.

10-Bit Posted at 9-19 08:48
Nice!

If you can confirm that it records 4Kp60 HB - 4Kp120 RS - 4Kp60 4:3 RS - 2.7Kp60 HS - 2.7Kp120 RS - 2.7Kp60 4:3 RS without any issues - that would be very much appreciated.  I ordered the Samsung 256 and OA3 a few days ago to replace my lost OA2 - but unfortunately will not be able to use and test until mid-October.

I made a test with 4K120 RS for a 2-minute-clip. All Okay. Reformatting Okay!!
Info by the camera for 4K120-Clips: max 9 minutes recording (overheating warning).

djiuser_zEKgdWRops1S Posted at 9-19 09:09
I made a test with 4K120 RS for a 2-minute-clip. All Okay. Reformatting Okay!!
Info by the camera for 4K120-Clips: max 9 minutes recording (overheating warning).

Thx.  On the OA2 used 2.7Kp120 a lot since there was no overheat limitation.  Only used 4Kp120 in specific use case instances.  But when I did my very many resolution tests and high ISO tests the IQ variance was not that significant.

However 2K IQ was simply average.  Pretty much the same as 10 years ago.  So did not use 1080 at all in OA2.  To fit in with super clean full frame Sony and Nikon 1080p60 footage - you need 4K in 1/1.7 to even come close to matching up.  

This was a comparison screenshot from a 1080 GP vs 2.7K DJI.  1080 in any tiny sensor action cam is real messy.

Aavalaakso Posted at 9-19 06:39
Like your sarcasm.

Sure we who manage University Server Clustering and run Virtual Servers we definitely buy everything from eBay.

Why do you answer like that?
I was serious because there are a bunch of people complaining on the forum and they bought cheap/fake cards and not from desent dealers.

johansenfoto Posted at 9-19 12:41
Why do you answer like that?
I was serious because there are a bunch of people complaining on the forum and they bought cheap/fake cards and not from desent dealers.

Because I wrote "Been IT professional decades". That should tell you that I know all about IT.

Yes I believe people who don't understand may indeed be scammed in everything and buy cheap 8TB ssd for 40 euros.

Always buy everything from qualified sources no matter is it IT or not. eBay is opposite of that.

No offence.