Pixhawk 4 SBUS out

hello all
iv been having a strange thing happen to my drone from time to time
i have a holybro pixhawk 4 with a tarot t-3d gimbal set up on pins 1-3 to control it
it works. BUT and its a big BUT from time to time the gimbal freaks out after arming the drone
its starts shaking from side to side and tilting up and down. and it keeps doing it even after i unplug and power up the drone.
so here is what in thinking the gimbal has sbus or (2 channel to control the pan/tilt) sbus gives me 3 channels to work with pan tilt and mode (mode) lets me switch between fpv and pf, (pf) from what i know is where i get to move the gimble from the radio fpv keeps the cam pointing forward at all times.
so if i can swap from pwm out to sbus out i can switch back to fpv if my gimbal freaks out again as it does not freak in fpv mode

what settings do i need to check and change to run the gimbal from sbus out ?
i use Qgroundcontrol
any help will be appreciated


here you can see what im talking about Tarot T 3D on holybro Pixhawk 4 problems - YouTube