Could you please supplement the pictures with some description of what's going on? It's hard to tell what's troubling you just from the images.
Have you checked the log files for any hints? I'm not sure which file to check; I'd start with /var/log/Xorg.0.log. Next time it happens, use the
tail command to look at the newest lines in the log file you are checking.
I don't use Cinnamon, but you might check /var/log to see whether Cinnamon maintains its own log file.
