Sorry for the bump, but i stumbled upon another really weird issue.
This only happens with my Gamecube and Sega Saturn cables (bought from retrogamingcables). I actually tried several Saturn cables.
If i connect these to my Hama 100S, which is hooked up to the XRGB Mini, the picture looks great, no visible noise whatsoever. When i start to daisy chain my two Hama 100S units, the signal gets noise that looks like a sort of moving moire effect.
Now here comes the strange part!
You might think the scart cables that connect the Hama units are faulty. I tried swapping these cables with high quality ones, but no luck. Also checked if one of the Hama units was causing the noise, but it was perfectly fine. So i connected all my other consoles (NES, SNES, SMS, Megadrive, PS1, Dreamcast) and none of these have problems with the noise, even when i daisy chain. The picture is clear and noise-free!
There must be something weird happening with the combination of the Gamecube/Saturn cable and daisy chaining the scart switchers.
Any idea what his could be? There's nothing wrong with the cables or the Hama switchers, i totally ruled that out now.