Ask HN: Safari 12 address bar issue?

Safari 12 seems to have this annoying new behaviour of ignoring my changes when I go to modify the URL in the address box. It usually takes a few tries before I can override it, even when the URL is to a completely different domain. Somehow I suspect this is supposed to be the result of some overzealous security feature that discards the inputted URL if it doesn't match the SSL certificate that's currently loaded for the page. Has anyone else noticed this?