Static Mesh with Physics falls through Terrain?

So I made a Static mesh with a blueprint on it that is used for my Inventory pickup. When I add the blueprinted static mesh into the game and then press the play button, the item falls through the terrain, once in a while it wont but once i step on it, it glitches my camera then falls through the terrain. Any ideas? (I tried this with a basic static mesh with simulate physics on it, same thing. there is a simple box collision on the mesh.

I had a similair problem when simulating physics on a ball projectile and essentially it was due to the fact that my collision mesh was not 100% fitting my object. I am guessing you have changes the size of your collision mesh?

Hey EscapeTheFate, did you manage to sort out your problem at all?