Forum:Category duplication

I've seen several pages (usually after an anon user edit) where categories are duplicated on the page, such as this edit. I'm just wondering why that is(I think I know the answer, but.....)--31dot 20:11, October 25, 2011 (UTC)
 * The new RTE. It's a bug that's been reported.  Several times.  But they can't seem to track it down.  *sigh* -- sulfur 20:45, October 25, 2011 (UTC)