Normal Decals Unexpected Lighting

Clip showing the lighting reacting in an unexpected way to the Normal decal.

Material graph.

Normals from the trim sheet (tangent space, directx)

What could I have setup wrong?

Could be screen space reflections? Try turning them off in your post process volume to see if makes a difference.

Thanks for the suggestion, I’ve just given it a go and it didn’t seem to fix it unfortunately.