Cube Black rebooting while in mission

Hexa with Cube Black, 3.6.12, flew a mission and seemed to have rebooted during the flight and came down. In the message screen it can be seen, that after having reached waypoint 39 it cleared the mission and some watchdog message appear. From pilots perspective it just cut off the motors.
The logfile shows messages concerning bad GPS and compass. Of course the pilot should have landed to check. But the question is why did the cube reboot? What is this watchdog?
Help is very much appreciated.
Tlog and fotos from message windows here:
https://drive.google.com/drive/folders/11lYCGu3NGLfiKNbWsMUZRschmqV6-1HI?usp=sharing

It might have been a power supply issue.

To investigate further we need .bin files. Not .rlog and not .tlog files.

We are not actively developing that version anymore.

Hi Amilcar,
habe dir ne Mail geschickt.