This is not a bug, as you’ve mentioned. This is a simple modeling issue that will need to be resolved in your modeling software (Blender in this case). The normals for the polygon’s faces are flipped the wrong direction. This is why your mesh looks like it’s flipped inside out. There is no face information on the backside which explains why you can see into the model and see the faces that way.
I don’t use Blender so I can’t explain the process to flip the normal in the program. But a simple Google search should provide sufficient results to get the normals facing the proper direction.