[1] Describe in detail the error you encountered.
Trying to use the tilt/roll widget but it forgets a calibration within a couple of minutes.
This is before calibration:

This is directly after calibration:

And this is 2mins later - car was not moved at all:

I had not unpowered or rebooted the radio in between. I don't understand why this drifts all the time.
[2] Provide a screenshot of the system information and take a picture of the system information in the pop-up window by long-pressing on the top-left image for 3 seconds in “Car Settings”-“About”.

[3] Is it possible to reproduce the error and what are the steps to reproduce the error?
Yes, 100%. Just calibrate and then watch it drifting or jumping. Keep radio powered up (after power cycle I would understand that the calibration is lost due to gyroscope having to come up again).