I use k90 keyboards and it's lighting functions always seem to break. Light modes don't cycle when I press the button on my keyboard to switch lighting modes. Same with toggling brightness - half the time it doesn't work. Feels like lighting settings never work correctly. It's definitely iCue because I use multiple Corsair keyboards and they all experience the same issues.
In general, the lighting UI needs to be overhauled. It's so convoluted how to create lighting profiles. The UI makes it really confusing to understand how to create custom profiles. I think a serious effort and budget needs to be invested in building out a better UI if all your high end peripherals utilize the software.
I won't get into the fan problems as it's been addressed multiple times but I hope you can phrase it to Corsair leadership that iCue's reputation is directly affecting company profits. I'm actually in need of new fans and I have actively avoided choosing Corsair fans because of these issues. And honestly won't be purchasing any Corsair product until iCue is in a better state. That includes PC parts. I hope iCue can salvage itself because I do like Corsair hardware.