Here is the ETMY HWS wavefront during the YAW oscillation - when the ETMY was yawing at 5mHz with an amplitude of approximately 30urad.

The wavefront a lot of noise in the top left hand corner and there is also equal amounts of pitching and yawing registered on the HWS.

Looking at the raw data on the camera, we can see that the top left corner is cut off in the measurement.