Hello, you had a null reference error in your original post so that will have been telling you that at the mentioned line of code the object being referenced there isn't being found, which will mean that you haven't set that object up properly. I do remember there being odd behaviour that if sometimes one character controller jumps at the right spot on top of another character controller the former would shoot up into the sky. I think that was a bug with the character controller. In your case though it sounds much worse. Double check that there aren't any other gameobjects attached to the player that have an active collider attached. Disable them if there are because I think they'd be colliding with the character controller continuously.