Under normal conditions, a post should only be shared once. However if the “Do note share…” checkbox is not checked, then the post can theoretically be shared every time the post is updated.
But under normal circumstances, when a post is first published, this checkbox should be checked automatically. So you may wish to check the post and see if that checkbox is checked or not.
The Checkbox “do not share is checked” – but in fact I don’t know if I checked it afterwards. unfortunatly ther ist only the publish date, no updated_date in the list. But within the article I have “Last edited 3 years ago.” – so I would assume, there wasn’t an update lately.
Very strange. I know configured “do not share” for all posts, so I will share “manually”. I will give feedback, if I see something in the future.
Maybe try disabling all other plugins and see if it happens? The plugin only doe share when an action event occurs, that is, when a post is updated or created. The plugin can’t share based on its own intuition or anything like that. So if a share happened it means a create or update event happened on a post. Under normal circumstances create and update events only happen if a user did something. But there could be plugins which do operations which might create or update a post.