no idea of what caused it, but i had that too.
a dude with no nick (just playerid-whuteva) was in regged classic. he was swearing all the time, whcih might mean he's a noob using a bug and finding it cool... i won him a coupleof times, he swore again and left. then i went to, i think it was judo or wushu, and there he was again.
i know a regged person can play without a nick, but he didn't even have the "+" in front of his name... couldn'y get a screeny though, sorry