Svarin
FCOM notes that Overspeed Protection provides "positive static spiral stability" which means neutral stick roll-wise will actively return the aircraft to zero bank, instead of maintaining zero roll-rate.
This is a significant departure from the way the pilot usually flies this type of aircraft manually. I contend that this would at least partly explain the roll control difficulties faced by PF from 02:10:16 until the top of undesired climb, compounding his ability to identify a critical flight controls issue on the pitch axis.
That only applies in Normal Law - in ALT 2 the roll control is direct - so no positive spiral stability. That is why the a/c rolled on AP disconnect instead of maintaining zero roll-rate.