i know using VATS with melee just teleports your guy next to the target but he's teleporting so close to the guy that when he extends his arm for a swing, the arm goes straight through the targets torso which ensures the melee weapon actually ends up behind the target and doesnt deal any damage.

if I am lucky i can hit when my character is not so close, but most of the time with melee VATS my guy teleports so close to the target that they're practically frotting

i don't remember having this issue on FNV but i know that FO3 has different melee VATS animations.