Getting the "shrink wrapping" effect even though I'm using $concave...

Okay, so I’m making this curved train track in Blender. I compile it, place it in a map in Hammer, all checks out at first glance. However, I walk over it and it seems like the collision model isn’t quite how I wanted it to be. I turn on the wireframe that shows the collision models only to find that the collision model is “shrink wrapped” onto the collision model I originally gave it. I tried decreasing vertices and splitting the curve in half, neither helped. I also did use $concave in the QC file. I didn’t see any errors in studiomdl either. Anybody have any idea what’s going on?

Do you have a screenshot of what you mean?

Here you go (wireframe is collision model):[/t]

And here’s what the collision model should look like (highlighted to show that it is split into two models):