I did test that part quite a lot, and if it runs after restart that sounds like a random accident. I'll double check the scene tomorrow and see if anyone else has had issues with it.
EDIT: Did you catch when exactly the freeze happened? I have a theory that Catherine entering the scene with her guards might cause a move route freeze if she and the guards somehow "step" on each other causing a blocked path. Never happened to me, but technically possible if your game happens to lag right then.