Shortly after installing Darkest Dungeons II, the cloud saves broke. The error message claims that the last time the files were synced was about 54 years ago.
I did not sync to either the on cloud nor on my compunter.

Also, the cloud sync of the first game, Darkest Dungeons, also appears similarly affected. However, booting up then quiting fixes the issue.

Anyone knows of a fix or workaround for this issue? Thanks in advance.

Sorry, I don't use cloud saves, so I can't help you. But if multiple games are affected I would assume it is a problem with GoG-Galaxy (which I don't use either). Maybe you should contact the support about it.