For some reason I keep getting a "duplicate post" when posting a reply and I only hit the submit button once.

 

Try clearing your cache, closing your browser, re-opening and logging back in.

 

It doesn't happen every single time, just now and then.

 

Its hit me a couple of times, lately, too. I'm going with the presumption that its a random problem with the servers on the back end. The technical explanation of what it probably is would take too long and hurt my head.