is it possible to create an Auto VTOL Mission that takeoff vertical and then when doing the transition to fixed wing mode will not try to change the yaw angle to the next waypoint while doing the transition? Heading to the first waypoint should only start after the transition is completed.
You could try using q_options to select do level transition, and then set the level_roll_limit to say 5 deg to keep it within that range until trans arspd is reached.