I’ve had the same issue off and on for months and reported it way back when via email. It’s intermittent but loss of keyboard focus on the intended window is pretty frustrating. I can usually “fix” it by clicking around other windows / tabs or opening a new window, navigating around with the arrow keys, closing that window, and keyboard focus usually goes back to normal fairly quickly.
Sometimes I get the system beep when focus is lost, and other times focus seems to be “stuck” in another window. I can have two windows / tabs open, each with a folder or file “selected” but I’m only able to control the “stuck” one. It’s definitely not limited to Visor.