I totally agree that it (at least part of the problem) does look like a back-face culling issue.FluffyFreak wrote:The glitching out of certain faces is probably due to the back-face culling.
That doesn't care about the surface normal, which is used for lighting calculations, it cares about the winding order.
However, regarding normals vs. winding order, my understanding is that Blender always keeps winding order consistent with the face normal. I don't think there's any mechanism to visualise or directly change the winding order of faces within Blender anyway, you can only display (and flip) the face normals, which makes sense since the face normal is much more intuitively meaningful. If I had to guess, I'd say it probably doesn't store face normals separately anyway, but just computes them on demand, and the control to flip the normal is probably implemented just by flipping the winding order.
I have not tried to test these things though. It should be easy to create a test model to check in the model viewer that back-face culling is doing what you expect, and then flip the normals in Blender, re-export, and check again.
John B