I agree that a little LR movement would be realistic, but what I am experiencing is not a little, it's quite a lot. Even when I go out of TC and go to the bridge it is obvious that the boat is turning sharply to the left and right. It isn't just a little "navigation correction" it looks like the helmsman is going full left rudder then full right rudder...repeat. Too many drinks I suppose.
I don't think it's stock as I've never seen this before and I always use TC since I have very little time to play the game and I don't want to spend it just sailing in TC1 looking for ships.