Tilt rotor servos tremble in Q modes

I have a problem with the tilt-rotor servos. When I connect the FC the servos tremble a lot in Q modes. But if I change to plane mode they stop shaking.

If I have Q_ARAT_YAW_P = 0.018 (default value) they tremble little, if I raise the value of this parameter to 0.5 the vibration increases.

I have the Pixhawk 2.1 Cube on silentblocks; I tried to leave it rigid in case the cause was too much antivibration but it remains the same.

I have also removed the Dragonlink Rx antenna by placing it in the middle of the wing but it remains the same.

At the beginning if I change to plane mode and stay in a few seconds when I returned to Q mode then the servos stopped shaking. But now this does not happen anymore.

Any suggestions?


I have noticed that the servos tremble in Q modes while on HUD it appears BAD AHRS and EKF in red. If BAD AHRS disappears and EKF changes white acolor then they do not vibrate.

This is well, but I do not understand why they vibrate with BAD AHRS.

IY have installed 3.9.4 ChiBios