Unparsable structured data – Incorrect value type ‘@type’

Google search console is showing an error `Unparsable structured data
– Incorrect value type ‘@type’ `

Here’s the highlighted text, the full extract is below.

"@id":"#webpage","url":"","name":"","isPartOf":{"@id":"https://scorpexuke.com/#website"},"inLanguage":"en-AU","potentialAction":[{"@type":"ReadAction","target":[""]}]}]}</script>
<!-- / Yoast SEO plugin. -->

It is only identified on 2 pages despite there being a couple of thousand pages in the site. Any ideas what the issue is and how to address it in Yoast?

	<!-- This site is optimized with the Yoast SEO plugin v14.9 - https://yoast.com/wordpress/plugins/seo/ -->
	<meta name="robots" content="index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1" />
	<meta property="og:locale" content="en_US" />
	<meta property="og:type" content="website" />
	<meta property="og:site_name" content="Ukulele songs and tabs by Richard G" />
	<meta name="twitter:card" content="summary_large_image" />
	<script type="application/ld+json" class="yoast-schema-graph">{"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://scorpexuke.com/#organization","name":"Richard G Ukulele Song Chords","url":"https://scorpexuke.com/","sameAs":["https://www.facebook.com/scorpexuke"],"logo":{"@type":"ImageObject","@id":"https://scorpexuke.com/#logo","inLanguage":"en-AU","url":"https://i2.wp.com/scorpexuke.com/wp-content/uploads/2015/04/header-image.jpg?fit=1260%2C240&ssl=1","width":1260,"height":240,"caption":"Richard G Ukulele Song Chords"},"image":{"@id":"https://scorpexuke.com/#logo"}},{"@type":"WebSite","@id":"https://scorpexuke.com/#website","url":"https://scorpexuke.com/","name":"Ukulele songs and tabs by Richard G","description":"1300+ ukulele songs and tabs","publisher":{"@id":"https://scorpexuke.com/#organization"},"potentialAction":[{"@type":"SearchAction","target":"https://scorpexuke.com/?s={search_term_string}","query-input":"required name=search_term_string"}],"inLanguage":"en-AU"},{"@type":["WebPage",null],"@id":"#webpage","url":"","name":"","isPartOf":{"@id":"https://scorpexuke.com/#website"},"inLanguage":"en-AU","potentialAction":[{"@type":"ReadAction","target":[""]}]}]}</script>
	<!-- / Yoast SEO plugin. -->

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