Thank you for reporting a bug to Unity.
We have reviewed the issue carefully, and in this case, the team is unable to prioritize fixing this bug. There are a number of reasons we make this decision, including the impact and severity of the issue across our user and customer base, and the possibility that future plans may solve the problem in a different way, or that a workaround for the bug may be available.
Today we will be closing this case. Thank you again for taking the time to report this issue, and please let us know if there is anything else that changes the impact or severity of this issue.
Additional context:
The issue comes from the topology of the meshes in question. MeshCollider by default uses "fast midphase" for cooking any mesh being passed. This logic inside the PhysX sdk builds a tree of nodes recursively based on how the mesh topology is structured. Changing the way this system works currently can and will impact anyone using this feature, instead what you can do to avoid the crash is to first add the MeshCollider component and then remove "Fast Midphase" from it's cooking options. This will ensure that you use the older somewhat slower bvh type for the mesh which will support these kinds of meshes. We are aware that newer versions of the PhysX SDK do not have this issue and are looking into what can be done from that angle in the future.
Cheers,
AlexRvn.