Even if it would be full, it would still appear on the server list.
Also, I had the same problem the other day, so I've tried doing /jo <servername> (eg. /jo GMTourney) and it seemed to be gone somewhere... It won't connect to it whatsoever.
Servers ghost because they momentarily lose connection to the server list and do not reconnect.
[23:23:53] <AndChat|700625> Blue eyes ultimate dragon best card
[23:24:29] <AndChat|700625> You know the one with 3 heads
[23:24:39] <~Lightningkid> just like my dick
[11:35:40] <box> Hampa suck
[11:36:21] <hampa> not the first to tell me that today