I don’t have a reproduce, a bug-report wouldn’t make it through I guess. But I wanted to let you know anyway.
Sometimes this starts happening. Then at the same time, keys such as DEL also no longer work ¯_(ツ)_/¯
I’ve forwarded the thread to the team.
I’ve run into this in 2019.4 as well, thought maybe I hit the “gaming mode” button or something on my computer. Restarting seemed to fix it.