Created attachment 402825 [details] video of issue I am unable to reliably recreate, but if I open a new Safari tab and type "google.com" and press enter, approx 2 in 10 attempts result in the URL being instantly cleared and no page loaded. I have no browser extensions installed.
This appears to be a Safari application issue, not a WebKit one. Could you please report it to Apple via <https://developer.apple.com/bug-reporting/>?