Superior Rune of the Thief
I’m assuming it uses the same function to determin if you are infront or behind/the sides as Giant Beetles in Drytop.
Giant Beetle will check if you are with about 40 degrees infont of it, aka if you drew a line out of the beetles face straigth forward, and one from his face towards you, the degrees diffrent between the two lines must be les than a certan amount.
It does not care about the AoE effects center or the projectiles origin, it only checks your position. So if you put a turret behind the beetle, while you stand infront of it, the turret will still deal dmg. But if the beetle turns towards the turret, and you end up behind it, the turret wont be able to deal dmg anymore.
This is a pretty large oversight in the code and ruins any interesting gameplay where you would throw AoEs behind a target to proc runes of the thief, or lure enemies to look towards you so a turret can hit them in the back.
This oversight is made even worst with NPCs that have core mechanics build around it (like giant beetles), for example, the beetle have an animation where it gets knocked on its back facing the other way, yet you still need to hit it from the game objects forwards direction that is still pointing towards you, then when it gets up, it will instantly turn around and any burst you tried to land is negated.