fgrieu, I think you'll find the A/C was in Alt Law 1 or 2 depending if it had concluded a ADR disagree or fault, either way the pitch control in Alt law 1 or 2 is the same, with normal THS movement dependent on the load factor command from the sidestick deflection.
Once the A/C exceeded 30 degrees AOA however the abnormal attitude would have kicked in remaining in ALT law however the THS auto trim would have stopped.
So the initial nose up inputs caused the THS to trim for the new commanded load factor from the sidestick deflection (full nose up at times) and frozen at 13 degrees probably when the AOA exceeded 30 degrees.