I see you have been around awhile. You dont say what model or kind of model. Did you do the mechanical setup?
With a default 1ail-1flap wing setting in the radio on an Acro model and you Bind the plane and Connect where do the Flaps go?
I mean what position are the Flaps with 0/zero/center in Flap System? The Flaps should mechanically pretty much be half at this point.
+value in Flap System should bring them to up from center and -value should push them towards fully down.Right?
It is better if practical to hook each servo on its own channel if you have enough Rx channels for it. It should work the way you have it
but dedicated channels for each servo is always best. Sometimes some servos just dont like to play nice when you pair them on a Y.
What Rx and servos are you using?
Most problems come from not mechanically centering the flap surfaces themselves in the middle of their range with the servos centered(Flap System 0)