Work vehicle magnetorheological fluid joystick systems reducing unintended joystick motions

The disclosure relates to work vehicle magnetorheological fluid joystick systems reducing unintended joystick motions. In embodiments, a work vehicle magnetorheological fluid (MRF) joystick system includes a joystick device, an MRF joystick resistance mechanism, and a controller architecture. The joystick device includes a base housing, a joystick movably mounted to the base housing, and a joystick position sensor configured to monitor movement of the joystick relative to the base housing. The MRF joystick resistance mechanism is controllable to vary a first joystick stiffness resisting movement of the joystick relative to the base housing in at least one degree of freedom. The controller architecture is configured to: (i) detect whether unintended joystick motion conditions occur during operation of the work vehicle; and (ii) when detecting unintended joystick motion conditions, command the MRF joystick resistance mechanism to increase the first joystick stiffness in a manner of reducing susceptibility of th