Mesh Collider strange behavior with box collider.

Quick Summary:

• Press play

• move mesh collider through box collider, nothing

• turn on convex

• move mesh collider through box collider, something

• turn off convex

• move mesh collider through box collider, something

Am I just retarded or is there some bug that causes this? I repeated this test multiple times Including turning convex on then off prior to any collision test, and i get the same result: no detection until convex is flipped.

More Detail:

I'm not sure If I'm doing something wrong, or if this is just a glitch, but I have the strangest issue: When testing to figure out why two objects weren't colliding (one has a box collider, the other a mesh collider) I tried setting the mesh collider to convex, and suddenly the collisions were being detected, I turn off convex (during the same run) and the collisions are still working just fine.

Disclaimer:

This issue has nothing to do with "The mesh collider needs to be convex" because, as described, the act of turning convex on then off made collisions work properly.

Notes: I'm running unity 4.0 pro