Problem - Normal Map-Based Game Lighting (Gen 7 Console Style)

Hello! I’m relatively new to blender (and 3d in general), but I wanted to make normal map-based lighting for low-poly characters, like Mario Galaxy apparently used.
I was able to find a system that could make my models look much smoother than they actually are, among other things, but I ran into a big issue.
When the light source is on one side of the object it lights 2/3rds of the total object. On the other side, it lights 1/3rd. I’m using a sun for lighting so it should be completely even on both.

Any Ideas on what’s causing this and how to fix it? Is it just a blender eevee problem?
Here are pictures of every step of the rendering process, to hopefully make it easy to understand.

Update: It does the same thing if I just connect the object normals themselves into the normal map node. 2/3rds lit on one side, 1/3rd lit on the other. Figured this might be important.