I ran into another small bug yesterday.
I was playing as the Witch, episode 4, against the Keymaster.
Because he has only one die, I aimed at the "Lock all dice" achievement. One of my spell was to lock the enemy die on a certain number (don't remember the name).
I put this spell on my 4 slots, put 4 different numbers in there to increase my chances at locking his only die, and managed to do so after a few turns.
But this method didn't unlock the achievement, even though his only die got locked this way.