ludgerarnold: Congratulations, you're now a full fledged necromancer! This topic has been dead for nearly 8 years.
About two thirds of GOG's catalogue were "dead" for a long time, a good portion for quite a while longer. I say kudos to people who take their time to write down the tips for a random googler stuck on a bug, today (whenever their today is).
xMrAx: Found a fix. This game is really sensitive to your mouse polling rate. Changing the polling rate to 125hz fixed this issue as well as removing movement stutter in the game.
Thanks a lot, this paired with compatibility options fiddling seemed to fix it for me, mostly. Turning off "enhance pointer precision" in mouse properties within control panel upped the consistency. Still occurs, but a lot less often and almost always disappears after app restart.