Certain channel prefixes are not supported in Colloquy and as such the client displays the users as normal users in the channel, not sorted properly but with their prefix in front of the name.
Further more, when opening a query with one of these users the tab of the window is the prefix of this user in the channel it was opened from.
Suggestion is to fetch the prefixes for channels when connecting to the server. Most IRC servers send them when connecting.
004: artifact.tx.us.msgplus.net Unreal3.2.3 iowghraAsORTVSxNCWqBzvdHtGp lvhopsmntikrRcaqOALQbSeIKVfMCuzNTGj
005: CMDS=KNOCK,MAP,DCCALLOW,USERIP SAFELIST HCN MAXCHANNELS=20 CHANLIMIT=#:20 MAXLIST=b:60,e:60,I:60 NICKLEN=30 CHANNELLEN=32 TOPICLEN=307 KICKLEN=307 AWAYLEN=307 MAXTARGETS=20 WALLCHOPS are supported by this server
005: WATCH=128 SILENCE=15 MODES=12 CHANTYPES=# PREFIX=(qaohv)~&@%+ CHANMODES=beI,kfL,lj,psmntirRcOAQKVGCuzNSMTG NETWORK=MsgPlus CASEMAPPING=ascii EXTBAN=~,cqnrR ELIST=MNUCT STATUSMSG=~&@%+ EXCEPTS INVEX are supported by this server
The channel prefixes can be seen there in the PREFIX= section. They're sent in their mode name (a,o etc) as well as their actual prefix (~, &, @, %, +) which is the order users with the prefixes should be shown in.
It isn't a matter of saying "I've never seen a server which does this" or "I can't find this in the IRC specs" because there are several servers which do and prefixes should always be fetched when connecting from the server info. If the info doesn't supply anything then it is fair to assume standard prefixes are supported.