Purple cube throttle issue

Does anyone know why the throttle stick works and is needed in auto mode on the purple cube? On my old pixhawks and the black cude in auto mode it ran what I set in the params. Thank you in advance for the replies. Its just more of a hassle to need to give throttle to start a mission in auto mode. This is for a Rover (boat)

I guess this is the ardupilot feature?


thats a good find, the problem is if the throttle is off or at one or 2 clicks going slow , the boat basically stops does some odd bucking does not follow course until i raise the throttle, totally odd.