Arm/Disarm Message Not Displaying and Cant Disarm Via TX

I am using a PIxhawk 6C in a differential thrust bathymetric boat. I have done all TX calibrations on my TX16S radio and can change modes and steer. However, I can only ARM my model and it won’t disarm via my RC5=153 switch.
I can ARM/DISARM via MP. In all instances, no ARMING or DISARMING message is displayed on the MP HUD . Arm Throttle and Disarm throttle messages do show up on the Messages tab.
Why is my TX16S switch not disarming and why is there no HUD display or ARM/DISARM state?

Thanks

Might help if you can share a .bin log file of the boat when you got it armed, and tried to disarm with the switch. Without a log everyone is just guessing.