A friend of mine recently bought a Freya, and he has a problem with it that we can't figure out.

The Freya shows no sign of any vibration during hover, and the tail is rock-steady, but if he adds collective a bit fast, the tail starts to shake sideways quite violently.

When the collective is reduced the shake goes away.

The Freya has a new GY401/S9253.
There is no binding between the S9253 and the tail (it's actually smoother than on my Sceadu, and mine works like a dream).
He has tried many different sensitivities on the GY401 with little or no result.

Anyone out there who might have a clue?