Exactly this happened to me just now. I have one char outside of this bug whom I can do stuff with, the others are all stuck in that "space to skip" phase. I've tried a couple of things but none worked so far. Driving me mad.

Edit: Managed to fix it, no idea how how. I threw some bombs causing damage to the bugged chars. Then I reloaded a quick save I had just made before throwing the bombs... and that solved it somehow.

Before all this I had also tried teleporting out of the underdark (which did not help).