I want to chime in on this one: I have the exact same issue. Everytime I boot my machine I have to unplug and replug my keyboard. It is also a Cougar 700K. My MB is an Asus TUF Mark2 and my machine is running Windows 10 Pro. I also updated to the latest bios, turned of fastboot in windows and the bios, tried all USB ports - no luck.
I'm lost.