I had a weird bug at the beginning of the library section in the Tower of Magic. When you go left from the entrance you have to push two blocks to reach the first statue, the second block being below the first. when one of my char pushed that second block, the entire level became unreachable except for the small platform where the rock used to be.
i tried to send a single char but the others still had no choice but rejoin him downstairs. i finally had to use the fast travel to the entry of the room after pushing the block and then i was able to reach the statue. only then i have been totally sure that a bug had occured.