no, it is not after an update, I can simply reproduce the error with the pve web... and I do it with the update as with any other action inside the pve web.But it happens after an upgrade, right? If yes I doubt it is your hardware. Have you direct access to the server (e.g. homeserver) and can you conduct a BIOS update?
I already have the latest version of the bios and as I said before, I was using the system for more than 7 months straight and out of nowhere it stopped working.
it doesn't seem to be a hardware problem... something with proxmox scheduled tasks or tasks done by pve web.
I am currently testing with a clean install without any updates from proxmox and so far I have not encountered any problems.