Hi Speedwinner,
I agree with the previous, especially Slasher's comment
lateral input is a roll rate demand
Sometimes in gusty conditions, a small side stick input may command full ailerons in an attempt to give you the requested roll rate. Any more side stick will have no effect - giving the impression that it is not responding - hence a tendency to over control and hit the stops. Try and keep the roll rate selections small and let the FBW computers decide how much aileron you need.