I was always taught to never let your knee go past your ankle in lunges. Why are your lunges do just the opposite. You push your knee way past your ankle?
I waa taught this also. Years ago. Turns out it was awful info. Check out KneesOverToesGuy. Hampton has actually referenced him a few times in his videos. Ive also used some of his techniques and have found a dramatic increase in knee health, durabiltiy and strength!