Definite Convex Mesh breaks when toggling on convex on Mesh Collider

Hi Im making a script that takes in a mesh, and based on that meshes uvs turns the mesh into a bunch of different meshes, and then uses those meshes on convex mesh colliders, Its working pretty well but it seems some, definite convex, with good normals, split meshes are just breaking apart as if the split mesh isn't convex.

This is the collider with convex off.

And Heres the same collider, same everything with convex on.

Btw in the future im looking to just have these boxes and other primitive type things be box colliders and the such but that will take a little bit longer and being able to just have every collider a convex mesh collider is quick for setting up and testing the map and its collisions etc.

Is this a bug cause i cant think of anything or other way of trying to figure this out, anyway thanks for any help.