Same for me.
My guess is that its to do with input overwriting the autopilot and subsequently disconnecting it.
If in straight and level flight with no yoke input autopilot does work for me but move the yoke even a millimeter and it disconnects.
My guess is that the fix is on ifly’s side, if they allow for controller lockout that should hopefully resolve this issue.
They also use different variables for yoke movement in general as the autopilot doesn’t move the brunner yoke like in the 737