I had the same issue.
I updated ICUE to the latest version 3.17. After restarting my PC it completely disabled my corsair headset. Had no sound, even when I tried testing it in sound properties an error popped up "Failed to initialize test sound" I've never even seen that before.
I had to make windows forget the device and reconnect it to get sound back. But then it only played in stereo. After numerous uninstalls/reinstalls of ICUE, I fixed that issue. But now, none of the EQ settings work.
I've uninstalled, used CCCleaner, reinstalled. Nothing. I've rolled back to an older version. Nothing. I've force updated the firmware, Nothing. I've uninstalled and used Revo Uninstaller to scorch anything Corsair related on my PC. Nothing. I even completely removed anything Realtek audio related. I updated Windows too just to piss myself off even more.
Everything sounds muffled and tinny.
Right now I've uninstalled it again, cleaned everything, and updated NVIDIA drivers and will see if after a restart and fresh install things change. I've also put in a ticket to CORSAIR 2 days ago.