I'm sorry if this has been reported before but it seems that I can't find a topic related to it.
Oh boy, I'm getting old. I found this out when I was testing RC3 few years ago (or was it a year ago?) when I had some rather serious business (well, it depends on your definition of serious

) and I wrote it down so I can report it later. Unfortunately I forgot about this until today.
Replication was successful on several sites running the latest SMF 2.0.2. It is replicable on this site. Simply, if you enable WYSIWYG and then enter an URL without the "http" prefix, for example:
www.something.com, it will be wrongly formated so now it will link to
http://www.forum.com/www.something.com.