Hello there, it's been a while !
I've found a bug :
If i use a bitmap (hdri mostly) in Reflexion override and not in the environment (lights), i get some strange rectangular errors in the render : longer to get less noisy and eventually turns black.
As soon as i put the same hdri in the light environment, instead of black color, it works.
Quick solution is to put the same hdri, but via one CoronaColorCorrection with expo to -20, so it is black for lights, but normal for reflexions...
