Content Duplicate

I’m trying to insert a table of contents in this post https://conectasoftware.com/prestashop/nuevas-caracteristicas-de-prestashop-1-7/
but when I add the shortcode, it appears the entire post duplicated at the end of the post (after the comments section) instead of the contact section that should be there (you can see the normal structure at this other post https://conectasoftware.com/analytics/que-es-una-fuente-de-datos/)
Anyone have any idea what might be going on?
Thanks!

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