Repro:

Create a spec/gloss map with a high specular value and a gradient across the surface. Setup a scene with 2 probes, 1 realtime one baked. Create a material using this spec/gloss map and assign to 2 planes. Place both these planes within the volumes of the respective probes. Disable "Force anisotropic" in quality settings.

Note:

The plane using the realtime probe will display very noticeable stepping across the surface.

Repro project attached.