I would ignore it.
Ive only ever mentioned a foot fault to anyone once after i was getting ****ed at not being able to get this guys serve back. He would start with his feet millimetres behind the line. step into the court 6 inches or more. Jump forward and land before ever contacting the ball he was probably 16/18 inches inside the line before he hit the ball. Never happened since i mentioned it, but unless you feel its putting you at a serious disadvantage then just ignore it
'Djoker who pummeled Nadal's BH and forced many unforced errors' OddJack
He is that good he can force unforced mistakes?! This guy has to be GOAT