So for classic photon caustics we need to disable “Affect shadows” in the material refraction so the shadows become dark and the caustics fill in the refracted light.
But for Quick Sun Caustics we need to enable “Affect shadows”, so the shadows become dark and the caustics fill in the refracted light.
My suggestion: Keep them the same, so affect shadows should be disabled for all caustics.
I get the idea of making it easy to just turn on caustics in the quick sun caustics tab and then it just works, but… yeah. I also like logical consistency. 