Can't calibrate DX3R/DSM2 combo with Mamba Monster

Strange things happening. DX3R binds with either DSM2 or DSM1 receiver. BUT when i try to calibrate with MM it does forward ok, then reverse ok, then will eventually do neutral after a longer peiod of time than normal!
The ESC then arms, but goes nuts, just like a run-a-way AM... no way to control it !

My old DX3 binds with the DSM1, calibrates ok, then ESC arms and works well :-)

I know the DX3R is ok, because I use it on another model with similiar specs !

Anybody run into similiar problems?