I guess I didn't explain the problem well. Its not that the page doesn't load.
What is happening is that the text of the page is displayed in a black and white pop up window. If I want to see the parent page I just click beside the pop up window which only covers part of the screen.
Sometimes it almost seems beneficial providing a focus on the meaningful content. Somehow the basic display behavior of Safari has changed. Not sure but I believe it only started after the last security update.
The same behavior show up on iOs and iPadOS.
I am also wondering if some of the extensions I am using could be triggering the problem: Bear, Devonthink, Send to Downie, OnePassword, Evernote, Instapaper, iBlocker, and Reader.
I could of course uninstall them all and if that fixed things selectively reinstall them hoping not to reinstall the source of the conflict.
That begs the question of why iPadOS and iOS are impacted as well.
I had presumed if it was a result of installing the latest update others would be seeing the same problem.
I guess I can also try reinstalling MacOS.
Thanks again.