I'm having the same issue, H100i RGB Platinum. As soon as iCue starts, I start getting usb connected/disconnected notification noises. every time that the disconnect noise plays, I hear the fans on the radiator shut off (and I'm reasonably sure the pump shuts off as well, given it seems to be managed through iCue). The fans will start to spin back up, and then the disconnect noise plays again and it all shuts right back off.
It's affecting my temperatures, and I fear for the safety of my CPU, should I put it under load.
Drivers are all installed at this point, only thing I haven't updated is the BIOS, but this seems to be a fairly common issue. I need a fix, asap, please...