The bug
Due to MC-87907 being fixed, an unintended side effect has been caused where endermen will not dodge the player's melee attacks if they are aiming at somewhere other than their head. They appear to "lag" in place (MC-101700) and fail to teleport, and effectively stay in the same spot. Since the dodging is caused by "looking" at the endermen while they are aggroed while close to the player, changing the "look" area also changes the area that triggers their dodging.
Previously they would dodge if you were attacking their torso.
How to reproduce
Spawn an endermen
Punch its torso area; notice how he
"attempts" to teleport(MC-101700) fails to teleport and stays in the same spot.Punch its head, it will teleport and dodge the attack.
You're absolutely right. Well played.