"Title" of the blog post image displays as an H1 and creates a pseudo post
When you fill out the "Title" field in the featured image of the blog post, something happens that the post takes de "title" of the image as an H1, so then it creates a SECOND page title at the end of the page, with the caption as the summary of the post, a second author (the person who uploaded the image), etc.
I'm adding a screenshot with the SECOND blog title highlighted. This title is taken from the "TITLE" field in the featured image. This appears at the end of the blog post, just before the footer of the website, but it doesn't always happen and I'm still trying to find what triggers this.