When the continue option comes up, does the game keep going in the background, yet that continue option freezes and is unresponsive?
The main menu still works, yet the actual in-game continue is broken. It seemed to work for a while and then it suddenly became broken.

More details for those who may encounter this:
the continue error happened even after restarting the game, and GOG Galaxy as well. However, after the next computer (Win 10) restart, it worked fine. So in the end I have no idea of what the issue may have been.

[Edit for spelling.]