MD-11 Pilot reported during attempted autoland before touching down the autopilot abruptly pitched down resulting in the crew taking manual control of the aircraft and executed a go-around to landing.

Narrative

Arriving in ZZZ an automated ACARS message requested an autoland be performed for aircraft currency. We attempted to perform an autoland to Runway XXL from an ILS approach. The approach was stable; configured; and the FMA (Flight Mode Annunciator) indicated DUAL LAND. Weather conditions were well within the autoland limitations and there were no deferred maintenance items that could have limited the performance of the autopilot. At the appropriate points on the approach; the FCC (Flight Control Computer) commanded ALIGN; FLARE; and RETARD. At an altitude of approximately 30-20 feet; the autopilot pitched up as if to flare; but before the main wheels touched down the autopilot abruptly pitched down several degrees as if it was derotating. The autopilot then disconnected without command. I assumed manual control; but the aircraft touched down firmly on the runway and bounced. We both called GO AROUND. I advanced the throttles; held the pitch; and pressed the TOGA switch. We recovered the airplane using the bounced landing procedure taught to us in training and then using the Go Around procedure. We returned for another approach and manual landing to the same runway. The Captain entered the failed performance of the airplane to perform an autoland in the logbook as well as to describe the firmness of the touchdown. Both we and maintenance verified visually that we avoided damaging the aircraft or scraping the tail before we left the airplane. I do not believe any limitations were exceeded; but want to include this report to add to the value of the program and for safety awareness. I was surprised how quickly the situation turned from stable to unstable and hope this report will help express the need to stay vigilant and be ready for the unexpected.One item of importance is that Tower and ZZZ Approach made an inquiry about the cause of the Go Around. I realize they have a job to report the go around and; to their credit; they didn't immediately jump in to start asking questions of us. But; because the cockpit becomes very busy during a go around and distractions are a real threat; the only good time to ask that question is by the Ground Controller after were safely on the ground when the crew can collect their thoughts on the matter together with open discussion. The Ground Controller can disseminate it to all interested parties.