THIS IS A PSA. Do not buy any Corsair cooling products until this problem is fixed.
Several of us have been having a problem with iCUE related specifically to using custom fan curves. Basically, iCUE's hardware monitoring software freezes. The problem is persistent and it doesn't cause iCUE to stop working, only the hardware monitor to crash and anything using it to stop updating. This means your fans will stay at a constant speed, your AIO will stop working.
If anyone is having any problems with their cooling, it is most likely because Corsair is refusing to fix the problem. All they have to do is recode only the hardware monitoring part of the software and the problem is fixed.
Below is the link to thread in the iCUE forum if anyone needs more information. And if anyone know a permanent solution, let us know.
https://forum.corsair.com/v3/showthread.php?t=178964