2008 Toyota Sequoia - intermittent shifting difficulty

Car has 167000 miles, will not shift into gear from parking randomly. Had to use the override switch all the time to make it work. Issue is that this is very random and will never occur when i take the car to the mechanic. I have checked the fuses for brake lights, checked the linkages for an debris or objects, checked the gear shifter knob area for debris or objects.