Double hmmmmm.

Oooooo. I looked up the Raptor and I take it you have the F-22 Raptor model? All bets are off. That has two outwardly angled vertical stabs and a single prop. You're probably getting the vortex of the prop wash on one vertical surface and not the other, which might cause it to react differently depending on the roll direction. It may never roll evenly with a tractor prop. If one stab is out of alignment with the other, or the engine has offset, that would further complicate a smooth roll with two large stabs. I believe some of the WWII German bombers and night-fighters that used twin tails had some problems in handling, also.

If you're also using the plastic "droops" it further messes with conventional model aerodynamics.

May be worth noting that the modern fighters are "fly-by-computer" and not just fly by wire; as the basic designs are unstable enough that a human can't fly them on training and instinct alone. I'm sure Hangar 9 modified the airframe to be suitable for R/C. But perhaps not suitable for FAI pattern.