Is it definitely version 3.1? Is it written in the menu in the lower left corner?
Are you absolutely sure that no mods were installed? Besides the Maps folder, there might be something in UserMODs.
I don't have the ability to check it on other computers right now. If anyone has it running normally, please let me know so we can understand the scale of the problem.

Update: Just in case, I reinstalled the game from scratch to make sure nothing interferes. On version 3.0, the map runs without problems, all scripts naturally don't work, and on version 3.1, everything is as it should be. I don't have any ideas about your glitches yet.