This is awesome. My last big complaint about lumen was the lack of high-quality multibounce, and this pretty much solves it.
I just quickly tested the settings- while it takes about 20% of my scene performance, indirect lighting is very stable, and if you need Archvis-like image stability, temporal accumulation matters less.
That said, I did notice some light-leaking with those settings enabled that wasn’t there absent, plus the probe occlusion artifacts (that I thought got fixed?)
Update: I found a bug: Applying your high probe count and temporal accumulation strategies to a lumen scene with a lumen scene lighting quality at 8, breaks indirect lighting.
When I pushed the hemispherical probe resolution past 4 for hemispherical lighting quality, the entire scene freezes up, and indirect lumen lighting stops updating entirely. That black smear is where I moved the cube in the lumen scene away from the wall; that said, direct lumen scene lighting is still updating. Do you think these more esoteric uses of lumen would qualify for a bug report @BananableOffense ?