Wow, that was a tricky workaround

But it gives an understanding of the proble nature.
Obviously problem was in configuration saved by previous DBeaver start, may be even by previous version of DBeaver. I never experienced such problem before, but it is possible.
Probably simple removal of .dbeaver folder (or, better, .dbeaver/.metadata folder) could help in this situation. It will remove all saved projects and settings but at least it will work.. Moreover it is possible to restore projects by copying their content from original (broken) .dbeaver folder.
Also I'll make more investogations of this issue to prevent it in future.
Thanks a lot for this information!