1. Was the autothrottle engaged?
2. If thrust was being managed manually was the autothrottle ARM mode used?
3. Was a normal go-around flown or was it a Windshear escape manoeuvre?
1. Probably when AP was flying it (but may have been disconnected to allow manual thrust control as conditions may have dictated, but on TOGA for missed approach regardless would have set initial thrust, then await further instructions).
2. Once TOGA is pressed, AT move up, if AT had been disconnected prior on approach, AT will not react further unless re-armed by crew during re-engagement sequence, usually when aircraft is being levelled out in trim.
3. It does not matter in this case, unless you are attempting to establish if crew (should have) disconnected AT as part of flown procedure.
Here is a thought:
On an ACQ manoeuvre, MCP speed window opens, if a low level altitude acquire happened then speed will be actual rather then associated flap speed, thus AT when selected will be reducing power with open speed window to establish commanded speed rather then required speed.
Add to this the possible FDs commanding the lower altitude which has been bust (as not set the higher FL080 in MCP) and FDs wanting to fly downwards (pitch forward), you need not think too long about what can happen next, when ballooning trying to re-ACQ the overshot altitude.
Another problem could be a vertical mode selection on MCP by crew: if the procedure is coded to have lower level off but MCP Altitude is set correctly at FL080, when Flaps Up, an MCP selection of VNAV may result in a descend under certain conditions when selected...