Hello
It's not the first time that I notice problems of rendering bug when I use 2 Sky.
Indeed I have well control the luminosity via the GI separately from the visible sky + reflection + refraction.
When there is only one sky I never noticed any bug.
It also does it with the HDRI
Moreover if we could control the power of each sky value it would be perfect.
This would avoid using 2 skies
Thanks for your feedback