Problem with Dual Rc setup, RC switching


I am trying to implement 2 RC inputs for my VTOL frame. First RC link(SBUS) is connected to autopilot via RCIN port. Second link(SBUS) is connected to TELEM2 port with an inverter(since SBUS is an inverted signal, we have to invert it to get data) and SERIAL2_PROTOCOL is set to 23(RCIN). Currently autopilot recieves both RC inputs correctly.

However, it constantly switches between RC1 and RC2 inputs. I am confirming this on Mission planner’s Radio calibration page. I also uploaded a video :

It seems like autopilot doesn’t changeover as the document( says and accepts any RC packet. Autopilot changes flight modes, deploys/retracts landing gear, enters simple mode erratically.
I tried this on Copter 4.0.7 and 4.1.0. both have the same behavior.

Any help is appreciated. Thanks.