Since I don’t see it linked here, here’s the relevant gitlab issue:
Also this post notes:
FP6 Random reboot issue
Issue reported on stock ROM as well. /e/OS developers are working with Fairphone developers for a resolution. Team has not been able to reproduce the issue. Request users facing this issue to share logs in the issue on gitlab . We are looking for details like the Service Provider details, information if reboot happened while travelling anything specific. Also wanted to confirm if the reboots started with v3.1.1 or were you experiencing them earlier as well.