The problem is called "SAS Nibble" and is due to the lack of enough friction between the sas actuators and the cockpit. There is a friction set on a bell crank just forward of the sas actuators that is cranked up to make the friction forward of the sas actuators higher than the friction back to the main servos. (The friction set looks like a coil spring and washer stack-up at the bell crank end.) The friction device assures that any sas actuator motions will work downstream, and make the main servos move instead of the cyclic. Because there is so little friction going toward the cockpit, the sas actuators are happy to just juggle the stick and leave the main servos sitting still.
The only concern I would have is to be sure there is no problem with the controls downstream of the sas actuators that makes very high friction, indicating a bad bearing or some kind of interference (wire bundle?) so inspect the system downstream to be sure it is healthy. If you open the system up at the sas actuators, the friction to the main servos should be smooth as butter, and almost zero friction.
PM me and I will send you my phone for more discussions if you wish.