Ah yes I remember using bent normal maps and reflection occlusion way back when it was introduced in the early 2000’s. For those interested - http://spherevfx.com/downloads/ProductionReadyGI.pdf
I guess, he refers to this video here, and the reflection capture part starts at 22.50:
Edit: But if in raytracing the max roughness is set to 1, then it should NOT use any reflection capture and blend with them. 1 was meant to be everything raytraced. So if now something gets mixed in despite the raytraced max roughness set to 1, then this would indicate a bug (who´s gonna report it? 
)
The only reflection capture, that would be allowed, is as end cap for the very last bounce, to prevent having a black surface reflected, if the reflected rays reach the bounce limit. It´s the cvar “r.RayTracing.Reflections.ReflectionCaptures” 1 to activate them, zero to deactivate them (they are usually off by default). And this function needs no reflectioncaptures placed in the scene, just use the cvar and that´s it.
I did. I’m guessing it gets vetted before showing up on the issues page.
The idea of the threshold property is for ray tracing to function the most, if not purely, at roughness value 0. In terms of mixing, it fades while getting closer to the threshold value, which if it’s 1, it’s no longer using ray tracing or is a complete mix of RT and other reflection methods. Ray tracing is meant to enhance reflections quality, and the threshold property, I think, offsets the cost / required conditions for it at higher roughness values…though the setting can be for lower roughness values too.
@eggboy5000 Perhaps what you could find useful is the threshold property of the reflection environment. It’s supposed to provide for the reduction of improper mixing between lightmaps and reflections, in particular from reflection captures because the captures use indirect specular and according to the doc…captures primarily reproject the diffuse of the area they’re encapsulating. It might explain how the capture probes by the cliff face are generating a darker tint of the grey coloring in the cliff material, which looks brighter when lit by skylight and directional, but is really a darker base color I’m guessing.
The cvars there could help in the mixing of ray tracing and other reflections such as captures. The rest of the page has pertinent information that may be important for getting better results in lighting a rough surface that is a bit reflective.