We are aware of the double/duplicate post issue. The IT people are working on it.
I’ve found out that we can avoid it. When you hit the “Post quick reply”, only hit it once, if it takes a long for the post to appear, DO NOT hit it again. That’s when the double post occurs. Simply CLOSE that page, not cancel the post, not hit the back button, or cancel or whatever. Just close that page entirely. Then if you want to confirm that your reply did get posted, open a new page and you will see it.