I have tuned my APM (without airspeed sensor) in a Skywalker for good FBW_A flight according to the documentation. Roll control is crisp, maintains ~45% on full-stick and doesn't lose altitude. I have also done a number of AUTO missions successfully (some several km's long).
I've now added an airspeed sensor and with no changes besides enabling airspeed, FBW_A is behaving badly. Entering and exiting a roll is very 'bouncy' and untidy. It looks like the roll axis is bouncing, but there could be pitch in there also. Once held in a turn it is fairly stable.
Given that it is FBW_A mode and there is no target airspeed or target altitude, why does the behavior change? Do I need to re-tune the servo pids?