I've noticed lately that when I have a remote session live on a machine, my local keyboard input is not being accepted in items such as Notepad, Chrome, Outlook, etc. This seems fairly system wide and I'm not always able to replicate the problem. This is likely something to do with the keyboard forwarding method, but I can't isolate this myself. Also, this does occur on several different machines - not one workstation in particular. As soon as I close the remote session, the keyboard functions normally in my local Windows 10 environments.
Good luck with this one - it seems very transient.