Going back or refreshing is not always a good thing!We may want to take a step back or constantly reload to take a fresh perspective of things, but it is not necessarily a good thing to do at ISC.
You submit a post, get an error message and either in total panic or out of perpetual habit hit the back button. At other times you decided to reload the page. A bit of advice - don't do either till you do this: open a tab alongside and check under 'new posts' and in the section's 'new submission' whether or not your post got submitted. You may likely find that it is indeed submitted.
In the case of articles section it is advisable to always type out an article first on your computer, save it there and then paste it here at ISC. An article is of a good length as compared to other posts, so it is not a good idea to type out the content directly here. You may even get logged out and all your effort will come to nought. Further, note that you should not press the back button once you have created an article and saved it. If you press the back button and re-save while creating an article, what happens is that a duplicate post of the same will appear under 'My Drafts'. Subsequently, when you do publish it finally, all unrelated keywords may also get attached to the article.
In the case of other posts too, even if it is a brief forum response or a short answer to an AE query, a good idea is to do Ctrl+A (select all) and then Ctrl+C (copy). That way, if at all you get an error message and find it did not get submitted, then you can always submit it with Ctrl+V (paste).
Another aspect you may likely see: When you submit something and then go to reload the page or close the tab, you will see a message "Confirm Form Resubmission - The page that you're looking for used information that you entered. Returning to that page might cause any action that you took to be repeated. Do you want to continue?" (see attached image)
You then have the option to click on 'Continue' or 'Cancel'. I would advise you to first check in a separate tab whether what you typed got submitted because if you click on the continue button, then your response gets re-submitted and you will see it in duplicate.