Joystick for mavlink overrides results in intermittent RC

# Bug Report I had a weird issue yesterday. I setup dual control as per the wiki - TX16S over CRSF for RC and TX15 as a Joystick connected to mission planner using RC overrides. When configured with a RC option of 46 the RC data appears to intermittently bleed through. To solve this I had to set the same channel on both the Joystick and the TX to 46 and then it seemed to work. ## Bug report - Setup TX (CRSF in my case) - Setup Joystick connected via mission planner (TX15 as HID device in my case) - Setup RC10_OPTION to 46 (RC override switch/disable) - If you only set up the TX to support RC10 then when in override mode and roll full right the RX display will show full right but with intermittent centering (I presume because the TX is centered) ### Issue details @rmackay9 @peterbarker might be related to the RC overrides channel bug **Version** What version was the issue encountered with **Platform** [ ] All [ ] AntennaTracker [X] Copter [ ] Plane [ ] Rover [ ] Submarine **Airframe type** _What type of airframe (flying wing, glider, hex, Y6, octa etc)_ **Hardware type** _What autopilot hardware was used? (Pixhawk, Cube, Pixracer, Navio2, etc)_ **Logs** _Please provide a link to any relevant logs that show the issue_