Hi,
Do you think there is a chance you are unvoluntarily changing the trim, which would disconnect the autopilot?
Can you try and describe more precisely what happens seconds before the auopilot disconnects?
Do you still encounter the problem when you uninstall or disable every additional plugin you have?
Regards,
Guillaume
Ps : please add more relevant and precise tags, so that the thread can be as useful as possible for others.