Reproduces with the latest master version of SRP (7dbf0b3017) on Unity 2020.1.0a12.1360 (40e46701fee5)
Does not reproduce with 7.1.2 release
Repro steps:
1. Use a project with HDRP
2. Create a new scene
3. Create a 3D Sphere and move it to 0, 0, 0
4. Make the 3D Sphere static and make sure its material is DefaultHDMaterial
5. Create a point light and move it to -0.6, 0.6, 0
6. Change the point light's mode to Baked
7. Bake lighting

Expected result: the lighting bakes correctly
Actual result: there are colored artifacts at the edges of the UVs, as well as colored artifacts around the lit area of the lightmap, where it should be grayscale since the light is white