Count me in on this one. I can tell you that Tells are included as well. I'll send maybe 4 tells in close time to each other (few seconds..) and 3 will go through but not the fourth. Oddly enough, I could re-type the tell or SHIFT+UP and
send again and it still wont go through. Everything before and after does. Length of tell doesn't seem to matter either (i type really fast); and zone doesn't seem to matter as well.
I haven't had any mouse clicks ignored but i've had hails not work and
/say as well. For me though, it seems to be random and not very often (sometimes only once a night). I would have more trouble trying to reproduce this ... which I know isn't helpful.