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The A/P was off. The THS must have moved in response to a S/S.
In this case it moved due to SS input.
To be correct though, THS moves also without SS input to hold the desired g, which would be 1 g without SS input. It has nothing to do with the autopilot on or off.
If PF would have only released the SS on his way up to the apogee (with decreasing speed) the FCS in ALT2B without protections would have deflected the elevators and in the following the THS Trim to full nose up to maintain the 1g (which is the demand with SS neutral) until the same result would have taken place, maybe within a somewhat prolonged timeframe.
Only positive SS ND input would have prevented that.