During the evacuation Mr Mahupuku tripped and fell, he then became disoriented and isolated from his partner.
He was alone in the building for around seven minutes with no one aware he was missing.
The report found there were several factors that contributed to Mr Mahupuku's injuries.
However, the two main causes were breathing apparatus entry and entry control procedures.
Firefighters either did not remove their apparatus "tallies" or left them in incorrect places.
The non-adherence to safety procedures was further exacerbated by a delay in appointing a dedicated safety officer, the report stated.
The investigation into the incident also found required accident notification procedures were not followed, "with the result that the communications centre learned of this incident from the media".
Fire Service deputy national commander Paul McGill said Mr Mahupuku has made a good recovery from injuries he suffered in the fire and has since returned to operational duties.
WorkSafe New Zealand also investigated the actions of the crews dealing with the Racetech fire, and concluded no action would be taken against the Fire Service or any individuals involved in the incident.