Hi DozyWannabe & salute Gums,
On page 112 Lateral parameters, Estimated side slip shows a distinct asymmetry after the AP disengaged. If I'm reading the trace correctly, it shows a Left Hand side slip DA. Since it was in ALT LAW, the the pilot will have to constantly apply aileron in one particular direction (LH in this case), until the side slip was trimmed to neutral.
I don't think the roll was turbulence induced because the effect lasted too long and would be random L/R. I think the aircraft was out of lateral trim (due some fuel imbalance, or asymmetric thrust, or rudder trim applied by the AP just before disconnect.)
All Boeing pilots are familiar with this problem, because we frequently re-trimmed the rudder during the cruise to keep the ailerons neutral. I've never had to do this on the Airbus, because the AP does it automatically for me.
If the FOs had never flown a Boeing, they would possibly not know about the requirement to re-trim the rudder to facilitate manual flying in ALT Law.