Compass calibration flight motors stop mid-air

I just did an autotune flight with the copter, cube black + herelink all axes tuned fine, no problem, copter behaved stable.

Then I set COMPASS_LEARN to 3.0 and armed to do a compass calibration flight. After a few minutes without warning my GCS says: “Warning stopping vehicle motors” and it falls out of the sky.

In the logs it switched to stabilize without reason and detected a land, red is the motors stopping, green the vehicle hitting the floor. Rangefinder is fine when it happens (blue). Flow sensor and GPS too.

Logs:
https://1drv.ms/u/s!AuKkq6JXpbFTzuN5RVIg4ii89z3lrQ?e=KXg2BP

Any ideas?

in the log it seems that copter switched to stabilize mode by your GCS !

Ok, I’ll check that with the Herelink guys. I have seen it at least once before that the app on the Herelink restarted, which is not a problem, but the copter changed to stabilize, which it shouldn’t.

But then then even a mode change should leave the vehicle still controllable. The last time that happened it just descended controllably.

Why did the land detector engage? And why did the motors not just do a regular disarm with delay, but perform an emergency stop so quick?