"fix dark glossy edges" breaks the RGlossiness (3.10.03)

[samuel_bubat]

While adjusting a floor material I wondered why it it would still render a sharp reflection of a window frame.
After some testing it appeared the "fix dark glossy edges" switch is responsible. It happens only with Blinn and Ward.
Attached are two images. Both are rendered with a RGlossiness of 0.5. The window frame is clearly visible in the
one rendered with fix edges on. It looks a bit like a Car Shader Material. Same effect happens also with very low values like 0.2.
I also tried various interior scenes of older projects and I can reproduce this effect, there.
It´s s not a big deal as you don´t need this switch for a floor nor did I notice it in earlier projects. Anyway I wanted to report it.

[^Lele^]

what's the shader cutoff value?
Make sure you render with it at 0.0.
Further, that option is MEANT to change the results (for those rays which would end up being traced below the surface, and contribute black to the results: no bug, that's why it was added.).
GTR/GGX being more modern and complex a BRDF, it suffers little to none of the original problem which had the option introduced in the first place.

[vlado]

It's not related to the cutoff, Lele; I know what the problem is, there is just nothing that I can do about it for the moment, other than recommend using the GGX BRDF in that case.

Best regards,
Vlado