Umbrel freezes every couple of weeks

I’ve had my Umbrel (Raspberry Pi 4 8GB) for a year now. I’m running 0.5.1 since 1 or 2 weeks, and today it froze again. I had to detach the power cable to reboot. Before the last update it also froze about 2-3 weeks ago. All in all about 4-5 times the past year, but mostly in the last few months. What could be the reason for this? How long is the average Umbrel uptime before needing a reboot? The RPi4 is using the official power supply and it’s on a UPS.

Yesterday it happened again. So my Umbrel was up for 14 days this time before freeing again.