From @westonruter:

FYI: When I run AMP on my blog with Jetpack it is catching these additional markup items as validation errors:
• Enqueued _inc/build/shortcodes/js/gist.min.js
• Inline script mentioning wpNotesIsJetpackClient
• Excessive CSS for modules/contact-form/css/grunion.css
• Enqueued modules/wpgroho.js
• Enqueued _inc/build/twitter-timeline.min.js