I've stepped through to verify that I have MTL::Buffer objects for each index buffer, but when I capture the GPU frame it just reads "indexBuffer: Null" for each draw. Is this just a bug? I'm guessing so as some of the geometry is appearing correctly.
drawIndexedPrimitives index buffer not showing up in iOS GPU capture?
I think I have figured out that this is simply displaying the name we chose and our code is using Null because the buffers in question were not named. You can nuke this post!