safari 15, this webpage was reloaded because a problem occurred

Mistakenly installed Safari 15 when I installed latest security update for Catalina. Now on some of the secure web sites I go to, I get a message "this webpage was reloaded because a problem occurred".

I can turn off Javascript and the page will load but, not all the way. Anyone else have this problem and know what the fix is for it. All works OK with Firefox just not the new Safari 15. Thanks