F and R keys on Razer Blackwidow Ultimate 2016 intermittently not working

Have not been able to find a pattern but, occasionally my F and R keys on my keyboard will stop working. I’ve removed keycaps and cleaned the buttons, and it has made no difference. With keycaps removed, and pressing just the actual button, it’s as if the keyboard itself isn’t registering the button press.

Drivers are updated to the most recent versions.