Yep, it seems it is indeed a mirc issue.
After testing with nikb we found that (as stated above) CR checks wether mirc supports the n!u@h format, then sends all info correctly:
<- :arena.webchat.org 353 Soultech = #mIRC :Soultech!jekz@=ndptw4-wyoc8-4-8-lwwb718.nott.cable.ntl.com basicer^!basic@=AJ42-783-556-06.dhcp.bycy.mi.charter.com EggHelpz!web@72.20.2.qj683= +nikb!nikb@staff.webchat.org ixpemCRWJn!mo@=qkeflj-69-311-480-83.dsl.rcsntx.sbcglobal.net @+basicer!basic@=AJ42-783-556-06.dhcp.bycy.mi.charter.com @jaytea!jaytea@=9Fkgyerwj-MBJ-vsj9332700.sympatico.ca
<- :arena.webchat.org 353 Soultech = #mIRC :HeadAcheLikeHeII!ALLOONE@=1Zoh.jb.147.31.revip.asianet.co.th Guest34758!h3lp@203.172.161.HX60= elder!technogen.@=9Np765-84-90.commercial.cgocable.net Guest38510!dol@=R1sfc-80.11.86.155.revip2.asianet.co.th Guest5988!mIRC@85.99.159.5O816=
<- :arena.webchat.org 366 Soultech #mirc :End of /NAMES list.
mIRC has no problems when loading the nick list for the channel, only when displaying it otherwise.
