Bail out, IMHO
1. If the ailerons had fluttered, you would not be here to report it.
2. Powered controls do not feed back force to the control column, they are irreversible.
3. With the autopilot engaged it is most likely that the autos moved the controls. If you do not like what the autos are doing – disconnect.
Most probably cause:- ILS interference from preceding traffic / autopilot mode minor instability when joining ILS.