I had this happen many years ago on a 757. On take off, fortunately, at low speed, the aircraft veered left. The takeoff was aborted and we stopped before we transited into the boondocks. Full right rudder had been applied to no effect. There were no obstructions to the controls and no obvious reason why it happened. We returned to stand and engineering found no fault. We departed with no further problems.
I am sure there are experts here who will tell me, how we could have done better and that our beer cans got trapped in the rudders. I bow to their superior knowledge as I only have in excess if 10,000hours on the airplane and it must have been my imagination.