After a while of troubleshooting, I found this option in the import settings in UE4: It was turned off. And when its turned off, UE4 does some random garbage on the imported collision.
It bothers me to no end that whenever I import a simple convex primitive as a collision for mesh in ue4, it always manages to mess it up! I even went as far as experiment to see if it'll be better if I manually check and triangulate every single face to make sure everything is convex. Doesn't matter. Here's an example,…