I’ve found it’s a bit fussy about control inputs with the autopilot engaged. I think I read (though not completely sure) that a control stick input kind of puts the autopilot into a roll hold mode. What works pretty consistently for me, if it’s not engaging properly, is to deactivate the autopilot, level the wings, wait for a few seconds and then re-engage, being careful not to make any stick movements. Then it seems to track fine. Hope that helps