Unexpected Motor Output

I am new to Rover but have had plenty of experience with Copter. I am not seeing the expected output on Ch1/Ch3 in Rover 3.3/3.4. Starting from a clean install connected to MP, if all I do is calibrate my radio, disable pre-arm checks, ARM in ‘manual’ mode and use the tuning function to monitor Ch1/Ch3 output, I am seeing an unusual response on the throttle channel where output is scaled between trim and max (~1500-1900). If I set the servo 1/3 outputs to be throttle left/throttle right respectively as required for skid steer, then the outputs on Ch1/Ch3 do not make sense at all with no evidence of the expected correlation between left and right (yes I reboot the Pixhawk after changing settings). This had me stumped for the better part of a night until I reverted to Rover 3.2 and everything started working as expected. Of course I would like to use the latest code - what am I missing? Is there some functionality added in 3.3 that is causing this? Assistance appreciated

It’s probably an issue with the SERVO1_FUNCTION and SERVO3_FUNCTION. There’s some documentation here on the wiki for how these should be configured. Beyond that if you can provide a dataflash log we can have a look.