Not sure why, but I think "The Hidden SWEP" was conflicting with it. I did a full enable 1 by 1 to find out which addon it was and 4 hours and 500 addons later, I found it. Basically, when you tried to enter the TARDIS it would stick you in a wall instead of going inside(ONLY FOR THE CAPALDI EXTENSION INTERIOR).

Half Life 2 Beta Props. Causes interior transparency and some other ♥♥♥♥♥.
Mods that mess with the camera ♥♥♥♥ some stuff up.

This is not exactly a conflict per se, but historically, interesting things would happen if you had something like the legs addon installed, where your legs would end up poking through the bottom.