Hi Oswaldo,
Not seen this before. So you have a section name called "Bloque 0", but now you are seeing it duplicated above, correct? Is Bloque 0 a normal section that is not hidden?
When you say in the code it says "hidden section name", if you were looking at the code inspector tool in your browser, can you post a screenshot of the browser with that code please?
Does the rest of the page look as normal? If you were editing the custom css, check that there are no syntax errors etc with the new custom css you were adding. Although can't see that this would be why.
Thanks,
Manoj