Shimano Zee Brake Vibration.

Anyone else had vibrations from a Zee rear brake?
Swapped from XT’s to Zees for a bit more power and the rear is vibrating just as it starts to get hot.
When it gets propper hot the vibration goes away again until i stop and it cools down.
Everything else in my setup is the same as when I had XT’s on.
Swapped pads and rotors front to rear/ rear to front and the problem stays at the rear.
Also tried metal and resin pads with no difference.
All ideas welcome.

Rear wheel bearings worn or rear axle/qr loose?

King hub with bearings adjusted spot on and 142 axle nice and tight.

something wrong in the calliper then?

That’s what I’m thinking.
Next plan is the swap front and rear calipers round.
Any more ideas?