Most are beating around the bush here.
HOT starts are normally caused by not enough, or unstabilized airflow thru the engine, when fuel is introduced.
IE, too much fuel, not enough air, results in a hot start.
Yes, it can also be achieved by having a tailwind up the tailpipe...unstable air THRU the engine.
The FCU rarely is at fault.
Follow the AFM (or your company specific procedures) for best results.