I bought a game about a week before. Its run amazing (5800X+6800XT+32GB) but all achievement show itself wrong , and the overlay window looks like strange. At all another gog game I havent same problem.

A new hotfix is available, it fixes some issues with the overlay.

Try it, maybe it will solve your issue

had the same problem. didnt fix it but achievements worked.

but when getting the achievement it will show as play more to get it but after a while it would unlock.