Normals Inverted on Part of Mesh

I’m running into a strange error I haven’t seen before.

I’m making some rock assets using all tilable textures. On part of one of them the normal seems to invert as it goes around the model. From above, one half is fine while the other is flipped. The transition is smooth between the two halves.

The texture that’s having the issue is on UV1, but works fine when I put it on UV0. I need it on UV1 though since I’m blending multiple layers that need different projections.

See attached pictures for issue.

Any help would be appreciated.