Oh boy, that could definitely be a problem - I just checked, and while I do have sort of an "update fonts" routine, it seems I'm only calling it before actually initializing all fonts via AddFontResource. Never thought that could a problem, as all fonts look correct in game.

Hang on, I'll give it a shot.

EDIT: Still no luck: Completely removed the AddFontResource calls. Fonts are defined right at start and never changed. Had the impression that it crashed later/after more attempts, though. But nontheless, it crashed several times during and after level change.