I click on Community to enter the Forum, then I click for example on The Silver Lining thread and this link is displayed:
http://www.postudios.com/blog/forum/index.php?PHPSESSID=xxxxxxxxxxxxxxxxxxxxxxxxxx&board=117.0
x= random letters and numbers
If I click it this message pops up: "You don't have permission to access /blog/forum/index.php on this server.
Additionally, a 403 Forbidden error was encountered while trying to use an ErrorDocument to handle the request."
If I reload the page or use Chrome or Safari this doesn't happen.
It's specific to Firefox on a Mac.
But I use Firefox mainly ;)
Only today I discovered that reloading the page solves it, until now I deleted manually all that long sequence of PHPSESSID...