This may not be related, but I run on Arch Linux with Cinnamon Desktop, and I found an issue where sometimes the Ctrl key’s internal state (but not the key itself) can get “stuck” and cause me to be unable to type. Tapping the physical key resets the state and all is well. I originally thought this was a UE bug, but I have recently reproduced it in terminal shell and a couple other apps, so I think it’s a Linux HID issue. Hope this helps.