Hoovering for test - Backflicks

I am hoovering at ± 1 m abg. Then after a short time the copter starts to shiver. Fractions of a second later it backflips.
In the attached log, you find crash at line 1157 and 2020. Can anyone good at analyzing logs please help me out?
It was a cold day, but the copter had been out for more than 20 minutes and should have reached a stable temp.

Could possibly be an ESC that is playing up.
also do you have a power brick? there is no voltage for the battery showing up…
please try running the motors at a reasonably high throttle for a while, and see if there are any further hiccups while the copter is tied down