duplicate posts?

[RedGTiVR6]

What would be causing duplicate posts from users?

I'm having a number of users complain of random duplicate posts when they are posting, and no, they aren't hitting the reply button twice.

it's telling them that they must wait x amount of seconds between posts, even though they haven't posted.

It will go ahead and submit the post, but it will also submit the duplicate.

I seem to remember this issue from before, but not well enough to remember terms to search on or even remotely enough to know what the answer was.

Any assistance would be greatly appreciated!