Ive just landed after a nasty bug occured in the googles.
I was flying around in M mode, when I suddenly noticed by altitude and speed were not updaing in the goggles.
controller was working fine, and video signal was fine - RC/HD and 4 bars, and I was flying pretty close

given there was a malfunction, I obviously decided to land...
so I switch to N mode to cruise back, the drone correctly switched to N mode..
however, the goggles did not show this .. so it was obvious now the whole telemetry data had frozen.

it landed fine, and was showing 40% battery left.
(everything in the OSD was still frozen)

now on the ground, I could 'reboot' the goggles.
as soon as they rebooted, the telemetry corrected itself... showing N mode, altitude etc.

however, the worrying part was ... the battery was at 20%, not 40% as shown on the goggles.

as I say, the drone and controller, and video were fine - it was just the telemery data that froze.

edit: observations
- just checked flight in dji fly app... and also shows data stopped around the time I saw the OSD stop.
- I did not get any battery alerts or notifications about RTH due to battery (which is a bit concerning)

Im downloading the aircraft logs... though not sure how to inspect this

Hello there thetechnobear. I am sorry for the trouble this has caused and thank you for reaching out. Let me please cascade these information to the designated DJI department for further evaluation. Thank you.

I also had this same problem. It seems to be related to batteries that get errors when updating firmware. I try to update my batteries but the update fails and that's when I have this issue. My battery that is updated seems to work without this issue.

Good Day
Re:frozen telemetrics on screen display
Flying my mavic air2 I have had this issue some 3 times recently and fortunetly the fpv kept working and I knew exactly where I was to return to home point but there was no update to the information on phone screen and I was fying with in my sight around open fields in the country and overall no more that 4-5 hundred metres max away.   It could have been worse of course however not knowing how much battery was left for example and so I landed safely and then turned everything off and started over and all was working.  
Finished my flights for the day and wondered what was the issue.. Does the telemetrics arrive in a different frequency to the fpv>?  Is my phone playing up although the visual fpv was fine.  Could there be some interference but no as I have this issue at different locations maybe not. I had bluetooth off wifi off and flight mode on.  
So the mystery continues -- I will take note of the batteries as suggested earlier here and keep an eye out for others who may have the issue.
Thank you in advance for any tips gretefully received

other topic about OSD issues pointed, that SD card full can also freeze OSD, maybe that did happen