http://www.wargear.net/forum/showthread/1698/You_are_invited_to_help_judge_a_WarGear_mapmaking_competition
Ok - it is editing a post that screws it up. If you have a link in a post and then you edit that post, it removes the 'forum' from the link (not from the text though).
Also - normally in a post you can just paste a http:// string, and the forum software automatically turns it into a clickable link. I did this when editing, & t was just text, but not clickable, so I edited again, highlighted the text, clicked the 'link (chains) button on the editor', and pasted in the http string for the link url & title. That also triggers the remove 'forum' bug.