No, there's no detailed level. Debugging shows all information sent or received over the network as well as the format in which it's being sent or received (such as PRIVMSG). That gives it more detail already than a standard log. Those are the very last lines in the log, right (unedited other than removing host info)? You'll need to wait and see what Khaled thinks when he sees that and if he needs any more information. I've tried reproducing it, but I don't have Japanese locale, so that may be why I can't crash mIRC using any of the combinations of text that you've shown.
