On the case of someone Copying and Pasting a line of text in Hexchat, a connected EiraIRC server will be partially disconnected. The text is only one way, from In Game -> IRC channel. I have 2 references to show the problem:
IRC channel: http://pastebin.com/69jHnDVf
In Game Chat: http://imgur.com/qArmg58
The possibility is that EiraIRC clients dont like the syntax that Hexchat uses (see the symbols in lower box of pastebin)
Thank you for reading :)

Was able to reproduce and get a crashlog for it, reason is a missing null-check for irc color codes not known to EiraIRC. Will be officially fixed for the next major release, but I've backported it to the current 1.7.10 version, available on my jenkins: http://eiradir.org:8080/jenkins/job/EiraIRC%201.7.10/