For those who made the jump from the Behringer X/M 32 Digital Mixers to the Behringer Wing Rack, the signal path from the mixer to your DAW is not the same. With the X/M 32 Mixers, it was Input > Preamp > LC – Expansion Card Out > DAW In. With the Wing Rack, the channel fader now plays a part as you will see in the video below.

EDIT: I downgraded the firmware and reinstalled the 3.0.6-25 version and everything works as it should now. The input into Reaper is set by the gain and the fader movement does not affect it at all.