Plugin seemingly outputting visible JSON in header

Hi, my clients website is showing the following code in the header since the update. When I disable Yoast it is gone. What’s happening?

{"@context":"https://schema.org","@graph":[{"@type":"WebSite","@id":"https://URL/#website","url":"https://URL/","name":"Sitename","publisher":{"@id":"https://URL/#organization"},"potentialAction":{"@type":"SearchAction","target":"https://URL/?s={search_term_string}","query-input":"required name=search_term_string"}},{"@type":"WebPage","@id":"https://URL/#webpage","url":"https://URL/","inLanguage":"en","name":"Sitename","isPartOf":{"@id":"https://URL/#website"},"about":{"@id":"https://URL/#organization"},"datePublished":"2018-04-03T13:22:15+00:00","dateModified":"2019-01-09T07:47:06+00:00","description":"Site description"}]}

Note: I redacted the name of the website

• This topic was modified 5 years ago by bartsaleswizard.