I just noticed. It just started happening so I am sure it is something I did.
When you go to forums, go into a group and select a topic to read you get a url like this
http://www.mysite.com/forum/#topic/Welcome-to-the-Forums-.htm
and it loads up fine.
but if you click on the Forum Posts block url I am getting this - both on homepage and in the forums area:
http://www.mysite.com/forum/topic/Welcome-to-the-Forums-.htm
and I get a 404
Somewhere the "#" isnt getting put in the url.
Where can I go to find this?