The A/THR can misbehave on finals if speed brake is used with flap during the approach and G/S tracking during speedbrake extension/retraction can be very poor, leading to some 'interesting' pitch attitudes and rates of descent (and historically many destabilised approaches) as the aircraft reacts to the significant trim changes.
Gear down ASAP to decelerate the aircraft rapidly below VFE, Flaps to FULL, 160 kts until reestabilished. Or throw it away and do it again properly, and don't be in such a hurry to disconnect the automatics next time!