Twice now when I posted a reply in a thread it popped up a red window that said something on the order of "Please post a legit message." or something similar but it posted the reply anyway. It doesn't stay on the screen long enough to read all of it.
I've seen that often when accidentally double clicking on a legit post, the site is fast enough that it believes I am trying to post a blank message on the second click.
Note:
I just created it again by clicking on Post message and then hitting that button again in about a half second.