Yes, as the editor of a couple publications, I’ve had new writers make a mistake and publish an article instead of submitting it to my pub.

Sometimes they panic, but really it’s no big deal. Even if they haven’t noticed for several hours or a day, I usually just advise them to copy the text, paste it back into a new story form, then delete the original article.

Now, if the article has already started to get readership, that might be another story, but for new writers not in a publication, that is not often the case.