Collision map importing incorrectly

I have a scene and a collision map built in blender. The scene is a collection of objects joined into one called “Ground”. The collision map is a collection of convex polygons joined into an object titled “UCX_Ground” When I import I uncheck “Create 1 convex hull for object”. So far this has worked with all my other scenes, though I only used rectangular prisms in them. I am exporting in the form of a .fbx

Here is a screencap of my scene before exporting.

And here it is after exporting.

Many of the vertices are in the incorrect places, some extending out into nowhere. At first I assumed it was because I stopped using only rectangular prisms, but some of the convex shapes imported correctly with no errors while some of the prisms did not.

Any advice on this issue would be greatly appreciated.

Edit: The rock walls are 5 convex shapes for each side, you can see the lines separating them in the picture.

Edit 2: I fixed the issue by remaking the shapes. That is placing new vertices at the old shapes vertices and deleting the old shape. The new shape should be exactly the same but exports properly. Is this a bug with blender? Should I move this question to the blender answers page instead?

as far i see they are not convex :slight_smile:

I wasn’t very clear on it in the question, but the walls are made out of 5 convex shapes each side by side, not one large non convex shape.