I was using CPU on Mac, also can't reproduce with GPU, maybe something platform-related.
I downloaded the latest build from the website, loaded factory settings, loaded all_light_types.ble…
I see weird artifacts with Automatic or Blue-Noise (First) when navigating in the viewport with 1spp, viewed relatively close. This is the all_light_types regression file.
Hm, I can't…
Given the number of changes made to shading since 2.79, I don't think this ticket is realistically actionable anymore.
Appears to be fixed in recent versions (presumably since 4.0 due to the new Principled BSDF).
Yeah, this is intended behavior - the Fresnel effect depends on the orientation of the surface, since it's different for light entering vs. exiting a refractive medium.
As a side note, a trick…