I have an odd little problem too
this only seems to occur with WinMX 3.31 clients
over a period of time, i seem to build up multiple entries for certain users in the userlist...
(happens with winmx3.31 and nushi)
3.5x clients (winmx 3.5x with bendmx, robomx, & even robo-based metis) seem unaffected
the WCS (WCS 1.8 Win32 rc3) involved is running on Windows 2000 Server with minimal additional software installed
i'm attatching a sample screenshot below..
Edit added WCS version details BB