If you're experiencing an issue with inconsistent or barely working melee collision while using Terraria Overhaul, ensure that you do not also have the following mods:

CoolerItemVisualEffects and/or ArnamentDisplay
These 2 mods (It's actually just two versions of the same mod) needlessly affect melee collision in a way that somehow conflicts and/or takes precedence over Overhaul's gameplay-focused arc-based collision.

Directional Melee
This mod may not be as harmful, but is unnecessary when Overhaul is already present.