I notice something similar has been reported on this forum in the past.
However during September 20 I noticed Airdata no longer shows Battery temperature over time for my MA2 (which uses the DJI Fly app).
I contacted Airdata and got this reply…
“The recent Fly app updates have caused the battery temperatures to not be reported in the log.
We’re happy to report that DJI reached out to us regarding this issue. They have identified the problem and will rectify the discrepancies in the next version.
The Airdata team thanks you for your continued support.“
So, just for information really, in case anyone else has noticed this issue. It will be fixed.