Here is the effect, easy to reproduce:
Version: iNav 1.0.1 release
Hardware: CC3D
Mixer: fixed wing
Mode: Passthru
Servos: 3 + 4
Connect a receiver, select passthu and set all servo rates to 0%.
Change pitch and nothing will happen, as expected.
Change roll and the servos move with 100% rate (Also displayed in the Motor-Tab).
I've tested the same with CF 1.12. release: works ok.