Beta v34 did not fix my problem.
Mine occurs solely whenever I have DevTools open while at the same time the Device Mode toggle is set to a mobile device as viewport.
Only my keyboard (and not my mouse) stops responding. That applies to the entire site I'm viewing with mobile viewport emulation but also all other input elements on all of the other tabs as well! Except the address bar, thank God. The problem seems to be limited to that; when I press the toggle again and click on the refresh button (F5 doesn't work yet) at least the keyboard responds again. But as things are right now, I am unable to test adjustments to websites for whom I'm updating their mobile versions and see the result instantly. Pretty annoying.