I have never seen this behaviour before and don’t know how it could have created the same tag multiple times. When WordPress adds a tag to a post if the tag already exists it just updates the count – it doesn’t create a new tag.
Are you trying to tag content with UTF-8 characters in it?
What does WordPress have as the values in the post_tag manager for these 3 duplicates? I know the slugs are different but what are the tag values?
I would just delete the extra tags in the post_tag manager in WordPress and ensure you are not tagging UTF-8 content.
Also once you have enough tags you can turn “auto-discovery” off and just use the tags you already have if you want / need to.
Can you give me an example post that has generated these duplicates?
If you’re not going to answer me I cannot help.
