If anyone stumbles on this thread like I did. I think I figured out the issue as mine was exactly the same but with SP Pro RGB fans. Same behavior.
On the Lighting setup of your AIO, make sure you set the fan type to none. It was set to 2 ML Pro fans.
Since all 6 of my fans, including the 2 on the H100i RBG Platinum are connected to lighting node core, iCue was getting confused. I set those to none, then my "test" of 6 different colored fans output properly after a restart of iCue service.
I can finally get my looping rainbow to output properly. Thanks for the guidance in this thread to help me troubleshoot.
