Weird RC Channel Pattern after issuing "RC all 1500"

Hey, as the title states, when I issue an “RC all 1500” the rc channels 3 and 5 behave weird. In the image, channel 3 is purple on the bottom, channel 4 is a flat line (1500), and channel 5 is pink on the top. As you can see channel 3 and 5 behave abnormally, and channel 4 remains normal. All the other channels besides channel 3 and 5 behave normally as they stay at 1500, while channel 3 is at 1300 and spikes up to 1500, and channel 5 is at 1700 and spikes down to 1500.
Please help me find the cause and troubleshoot this problem.
Thanks.

Do you have a joystick connected to the system anywhere, or do you have the ‘virtual joystick’ option enabled in QGC application settings?

I tested the RC channels manually through terminal, without a joystick connected. However when I connect a joystick and control it, everything works as expected. However my goal is to be able to control the BlueROV2 using mavproxy modules instead of joystick control.

I am asking because a joystick connected will conflict with setting channels programmatically and produce the results you describe.

What version of ArduSub are you using? You can see it in Vehicle Settings->Summary->Frame

Does anything show up in mavproxy console if you enter watch RC_CHANNELS_OVERRIDE or watch MANUAL_CONTROL?