After a little browsing I recognized that my issue might (also) be related to this bug: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/200509 (Microcode SW error)
So, if installing the backport module fixes this issue for the others experiencing the problem (without having the Microcode SW error), my current problem might not be related to this bug, but to the #200509 bug. In this case, sorry for spamming :)
After a little browsing I recognized that my issue might (also) be related to this bug: /bugs.launchpad .net/ubuntu/ +source/ linux/+ bug/200509 (Microcode SW error)
https:/
So, if installing the backport module fixes this issue for the others experiencing the problem (without having the Microcode SW error), my current problem might not be related to this bug, but to the #200509 bug. In this case, sorry for spamming :)