Major Confusion. . .

Ok, I've been seeing wierd things here.
First, when I post something using quick reply, it says "This is a duplicate of. . ." when I hit the replay button once.
Second, Sometimes, The page looks like someone posted the same thing twice in a row. It would be the exact same message. (This even affected one of Rukario's posts. It was freaky)

Does anyone know what could be wrong?

The double post thing made me post saying Rukario double posted (Just asking why). Then after I got back to the thread after the "Thank you for posting" message, Rukario's posts were now one. Then I had to go back and edit my post that asked why he double posted. I'm so confused. . .

Sometimes when the PC errors out it will resubmit your post making it seem like you've double posted. It just something you have to watch while the error get sorted out. :\

That happens when you press the post reply button twice in a row.

When PC is laggy, or has an error, hiccup, or has an error then it'll glitch like that and it'll double post sometimes (or try to double post and thus why you get that error). It's not because you pressed the button more then once (like Elite Salamance said), it's just due to PC's server having a little prob at the time.
And if you do "double post" like what happened with Steve/Rukario then all you got to do is click "Edit", and then "Delete", and the bubble and "Delete this message". That'll fix your double post probs.