UI Calendar showing two of today

So here's a weird one:
Screenshot: http://i37.tinypic.com/2ikev5.jpg
Obviously that is a problem :-(
I don't even know where to begin to diagnose and fix that problem
i'm using version 1.5.2, and tried it across Firefox and IE and see
this issue.....
Any ideas? anything more i can post to help diagnose? (screenshot
is from our intranet app, no public/outside access)