Ironically, when I posted the above post, I first got the message (approx): "You are only allowed to post once every 30 seconds. Please try again in 30 seconds."
What? I posted twice within the same second?
So, I waited 30 seconds and hit submit. This time it told me that I was trying to post a duplicate post and redirected me back to the thread, where the post had in fact been accepted.
Edit: When posting this post, I got the error message: " 1. This forum requires that you wait 30 seconds between posts. Please try again in 29 seconds."
And this time, I tacked on the edit, while I was waiting out my 29 seconds. So when I hit submit after waiting, it accepted the new post (with the edit), but had also previously accepted the old post. Looks like each post submission is automatically resulting in a pair of duplicate posts, the second of which is rejected, due to the 30 second rule.