After using Dynamic Harmonic Notch Filters,copter remains drift at Yaw

Hello your guys,Do you know why happens that copter is drifting slowly at Yaw, after using DHN_Filters( Throttle-based Setup was used).I finished PID adjustment.By the way, when thrusting up more than 50%,the copter will rise quickly at altitude,but keep to throttle(also more than 50%),the copter will showly be falling down.

@BryanFly,

Have you got an onboard log we can look at? Maybe the vehicle is suffering from high vibration levels but it’s just a guess at this point.