Hi, so at the end it seems the problem was running Duplicati with external Backup in parallel to any other Copying/Backup inside of the array.
It was causing long CPU and RAM spikes which made my system unresponsive. Docker Apps and VMs were still reachable and responsive, but Unraid itself was not.
I changed to Borg Backup now for the external Backups, did not have any error or hiccup anymore since then. CPU and RAM spikes went away.
Still have to do the MEMTEST, did not do that yet.
