Are there any updates on this issue?
I just purchased some additional Corsair peripherals (mouse, keyboard, mouse pad) and I was hoping to be able to have all of the RGBs in sync with each other. Unfortunately, with the archived version of the software that I was using two of the devices' RGB's shut off when I opened CUE. So I opted to try the most recent version of the software, which got all of my lighting working correctly, but then this sidetone issue re-emerged for me.
Fortunately I'm able to just close CUE to restore my sidetone functionality, but now my RGB's are a little obnoxious.