Reproduction steps:
1. Open the project
2. Open the "UV1map" scene
3. Activate "Sphere_secUV1" gameobject
4. Notice that the highlight reflections are no longer rendered correctly
5. Activate "Sphere2_secUV1" gameobject
6. Notice that the Specular Highlight is inverted

Note: Enabling "Swap UVs" on the mesh and setting UV0 set on the material resolves the issue.

Expected result: Specular Highlight is working correctly with both UV1 and UV0 set as UV Set
Actual result: Specular Highlight is rendered incorrectly with secondary Maps UV sets set to UV1

Reproduced on: 5.5.0b3, 5.4.1p1, 5.3.6p4.