Tailsitter violent yaw during takeoff

During Takeoff, tailsitter keeps yawing continuously. Also Y_des is non zero and large, despite giving no inputs from Remote control for Yaw- rate, as in attached screenshot of the log. (Green is for y_des, while red is for RC_IN

I have recently seen something similar, although maybe not that severe. In my case, the solution was to swap left and right servos, because I have seen these servos accelerating any yaw disturbance instead of dampening it.

(I have videos for both kinds of behaviour, but yet need to edit them and to upload).

I have the videos now. If you have something similar to the first one, then your solution may be just to swap the servo functions.

1: Default assignment, mad yaw spinning.

2: Servo functions swapped, normal flight.