Hi everyone!
Hope anyone can help me diagnose the issue, I have a strange problem with roll axis moving limits when MavLink is connected.

Several wodrs about setup I use. FC - Pixhawk Cube Orange, SBGC Extended V3,1 - gimbal board. Camera and Frame IMU (above YAW) are installed and fully calibrated. Encoders AS5048A (came with IFLIGHT gimbal motors) are installed on each of 3 axes. Im trying to connect Cube Orange FC to SBGC via MavLink to eneble several controll channels for different axes. I used RC_roll, RC_yaw, GND WIRES as a second UART for connection.

Trouble description: When drone and gimbal are started everything seems to be OK. I can rotate frame and all axes reach hard limits. But when I turn on my remote controller ( radiomaster TX16s) to controll pitch or yaw tilt (I use controll only for 2 axes), my ROLL axis become very weak and doesn't try to resist outer force(hand) after 20 degrees of rotation. Also when I try to set the roll axis to zero using API virtual channel it only tries to center axis, but can't reach 0 deg. This happens only when remote controll is turned on (if I try to do the same from GUI i have no problems).

Also I heve a lot of parse errors in mavlink 1 channel. But the strangest is that Pitch and Yaw controlled perfectly, only Roll becomes weaker.
Dear colleagues, hope someone can help to solve this issue. Thank you in advance!