T-Rex 450 - Beastx - Rudder action induce left/right drift

Hi,

I have recently installed a BeastX on my 450 Pro. It works very well except that when I apply an action on the rudder, the heli drift left or right (depending on the rudder action).

This can be countered by a small input on the left/right cyclic...

Any idea?

My setup :

T-Rex 450 Pro V1
FBL Head T-Rex 450 Pro V2
CC Ice Lite 50
BeastX v3.08

Thanks in advance!