AI Stacking Issues
Melee Push occurs always when attacking inside of “max-melee” range. When you’re at the range where there red “out-of-range” bar appears underneath your skills, but you can still hit the boss you’re in the “max-melee” range. At that point you can still hit the NPC with melee weapons but they will not be pushed by your attacks.
The Battle Bakery [vPie]
You answered yourself for #2, and Errant’s answer is correct for #1. To avoid melee pushing while still being either inside of the mob’s circle/right by it, you need to be attacking in the opposite direction against a wall/object with the mob against it.