Normal Faces Visible Through Model (Not BackFace Culling)

So applied a lambert as a material to test some textures, and the front faces on the opposite side are visible through the model. I'm already culling the backfaces and hardened normals, so I'm not too sure what else to look at in terms of common issues. It defo prolly something simple, but any help would be appreciated.

https://preview.redd.it/e0rwra7jgkof1.png?width=974&format=png&auto=webp&s=ad84d7939fa0d0b6ce10a7c834b83a3034707266