hello 47flatfender,
in my opinon i suppose the RX to IBU2 cable connected to CH1 (throttle) is faulty, if you have a Ohm meter available check the white wire.
In case the problem is this (i'm 99% sure about) you will need to match again the board with TX since the calibration done with missing channel signal (same as a faulty cable) will not work.
Regards
Ivano