My friend and I have been playing the Standalone on Steam quite happily for a few days, when today, we join in and his camera pans very slowly on its own with no input required on his part. At first it was left to right, and now it is top to bottom. He can still move it himself, but it makes it extremely difficult to aim and move. We have confirmed this is not an issue with his mouse and it has also been fine until an hour ago. Thanks for any advice.