I'm deploying to Vercel. When inspecting my deployed project, I see one of my third-party script tags added AFTER the end </html> tag.
I've googled and asked Vercel support to find any reason for this but without luck.

Here's how it looks:

  </body>
</html>
<script async data-explicit-opt-in="true" src="https://vercel.live/_next-live/feedback/feedback.js"></script>
<script type="application/ld+json">
{"@context":"http://schema.org","@type":"Product","name":"((REDACTED))","sku":"((REDACTED))","description":"","url":"((REDACTED))","offers":{"@type":"Offer","priceCurrency":"USD","price":825,"availability":"InStock","seller":{"@type":"Organization","name":"((REDACTED))"}}}</script>

This only shows if I fetch the URL with a limited browser (like Schema validator or a GET request in Postman). In Chrome I don't see the script, so I guess it depends on the user agent.

This only happens on Vercel - running locally or deploying on Netlify with the same setup I don't get this strange behavior.
So I suspect Vercel - also because I see their feedback component script added.

Did anyone encounter anything like this before?