Pathing Qeynos Aquaducts issues

[Deadswitch]

During my leveling down in the dank underground I've noticed a bit of bad pathing. Mostly mobs going from point A to point B in a straight line, cutting corners or straight up walking through walls to do so.

By the nesting rats there is one spawn that just goes straight south through the walls.
The tunnel by the mercs has some mobs going through the walls occasionally. No idea where they came from/are going though.
Anytime there is a bridge over the water, mobs that should swim under it are popped up onto the bridge then back into the water once they pass it.

A few potential mob issues as well.

I've only seen piranha in the cubert area, nowhere else.
I saw Drosco, had to hide cause he'd kill me, but he just disappeared. Wasn't even on track when I checked moments later.
The Undead Knight flees at low health. Not sure if he's supposed to do that, being undead and all.