Comment by TeMPOraL
10 hours ago
I'm guessing it's the HDD that's failing. Had such mysterious failures with my NVR (the Cloud Key thingie) from UniFi. Turns out, HDDs don't like operating in 60+ degree Celsius heat all the time - but SSDs don't mind, so fortunately the fix was just to swap the drive for a solid state one.
I think it was the DRAM on mine, oddly. It already uses an nvme ssd. Could have been the CPU, of course - the error was manifesting as memory corruption but that could well have been happening during read or write.