There have been a lot of double and triple posts here, probably because some browsers don’t give feedback while a form is being submitted, or users just miss the feedback and click the post button multiple times.
It’s pretty easy to use JavaScript to disable the post button after its clicked once which will prevent this and keep the forum tidy. Maybe the screen could also darken or have some other feedback to indicate that progress is happening.
There’s a bug at the moment where it is feezing or appearing to freeze when in fact it has posted. People press post again because it appears to not be moving. It didn’t even show a waiting for status in the status bar. That’s why there are so many double posts at the moment I think.
The lack of visual feedback when you post a reply definitely has caught me going “did it work, did I really click it?” a few times 
Fixed. The button is now disabled when clicked.
Had to remove the double-post protection, because it interfered with other stuff.