You can configure motion controllers (including turning them off) on the motion cotroller page of the vorpX menu.
As far as the underlying issue is concerned:
Quite a few games can’t handle simultaneous mouse and gamepad input. Since vorpX often provides head tracking via mouse emulation, the only way to have a working gamepad together with mouse emulation head tracking in affected games is intercepting gamepad input and converting it to mouse/kb input. That’s a feature not a bug. The gamepad to mouse/kb mapper is a fairly feature rich program in itself and fully configurable.
If you don’t need/want head tracking, you can disable the ‘X-Box Gamepad Override’ option and set the headtracking sensitivity to 0. That will bring back the game’s native gamepad handling.
BTW: With ‘X-Box Gamepad Override’ set to off you can let vorpX emulate a gamepad with head tracking, which in principle also deals with the issue. That’s generally quite laggy though due to the heavy filtering games usually apply to gamepad input.