I posted a video in the YouTube thread, then went back into the post to correct a mistake. After hitting "Edit" it treated the edited post as a new post. Thinking that I had accidentally hit "reply" or did something wrong, I went into the second post to label it as a double post, but it then treated that as a third post. I don't know if it's relevant, but the page rapidly jumped up and down about a dozen times while the post was being submitted. This is with Firefox running on OS X.