Posts being submitted twice

[Erin]

Consistently getting this error after submitting a post:

The following errors occurred when this message was submitted:

1. This forum requires that you wait 30 seconds between posts. Please try again in 30 seconds.

For what it's worth, I get the same error sometimes on my own vBulletin, too. I was hoping this problem would go away with 3.6.

[Chris]

I'm guessing its something with how your browser interfaces with VB, since it happens on your forum too and I haven't heard any other complaints.