VTOL transition throttle drop for very short time

Hi, I would like to know if this behaviour is normal. After taking off vertically, my VTOL start to transition to FBW to reach the first waypoint of a mission. During the transition, there is a very short time where the all the motors drop to zero. This does not affect the flight and the plane continue its transition successfully. That being said, I would like to know why is this throttle drop present and if it is normal. Thanks


In this capture rcout.C9 and C10 are the two front tilt motors
Frame is tilt tri vectored qplane