Basecam mavlink hanging problem

Hello, we run an Alexmos board with encoders on our custom built gimbal. We have a problem with mavlink hanging after few seconds. It looks like everything works and i can control the camera at full potential (rc_targeting, gps, ecc ecc), i can move it with joystick and can see all mavlink messages come trough the connection if i look at it on alexmos software. Than all of a sudden mavlink link hangs up and gimbal is not controllable anymore. If i restart gimbal than it works for a short time again and hangs up again.

I checked rechecked and triple checked connection and setup and it is correct (if it wasn’t it would not work for 20-30 seconds before hanging up).

I wrote on basecam forum and opened a bug report on basecam site about 15 days ago but, apart from 1 generic message, we did not get any assistance from basecam. Hopefully someone is having the same problem and can help us out in solving it.

Arducopter 3.6 RC10 ChibiOS, but it does the same on latest stable 3.5.7 Nuttx

Firmaware on basecam is latest beta for encoder 2.60b8 but it does the same on latest stable 2.60b4.