I was experiencing telemetry freezing using Herelink and in my case found the following fixed it for now.
This setup was tested on 2 identical drones, same symptoms and same fix worked.
The Symptoms
Normally fine on startup and for a few minutes use.
Values to the right freeze such as height and the mini HUD
The top bar would freeze values, no voice or text when changing flight modes
Some times it would come back after a few minutes
Video stream was perfect through out, no breakup or hanging.
What I tried
After looking through the forum I found a few suggestions.
Turing off internal location settings (no effect but best to turn this off anyway)
Opening and closing the mini map using the 3 arrows
Reinstalling the Herelink firmware (on latest V0.22)
Re binding, and checking with different air / ground units
Different reginal settings CE, FCC…
In this case what worked (or is currently working)
The drones are fitted with forward facing Lidar used as a proximity sensor, on removal of these and reverting the parameters then removing the value tab from the right of the screen that was set to forward distance the problem for now has been resolved.
With the problem sometimes not showing at all or after 20 minutes, at this stage I cannot be fully sure this is the fix but it has not reappeared since removing the proximity sensor.
Possible causes
I assume this could be to do with some messages not being understood in QGC from the proximity sensor.
If you are experiencing similar issues it maybe worth checking if you have added values to display on the herelink, remove them and see if this helps.