I've taken a look and after a lot of digging, trying to figure out what was going on, it appears the normal map is fine. It's the obj file that is the problem. I'll add the fix in the next update, but in the meantime, this can be done manually with a very small edit to the Wing_Right.obj file.
Back up first!
Open the file with any text editor.
The header (section at the top of the file) is missing the "NORMAL_METALNESS" line. Make the edit to ensure the header looks like the image below. (Do not change anything else)
Let me know if this fixes what you need.