[wp-trac] [WordPress Trac] #52768: WordPress post URL oEmbed rendering blocked by iframe lazy-loading

[WordPress Trac]

#52768: WordPress post URL oEmbed rendering blocked by iframe lazy-loading
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 Reporter:  SirStuey      |      Owner:  (none)
     Type:  defect (bug)  |     Status:  new
 Priority:  normal        |  Milestone:  Awaiting Review
Component:  General       |    Version:  5.7
 Severity:  normal        |   Keywords:
  Focuses:                |
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 After updating to 5.7, WordPress post URL oEmbeds are not rendering
 properly, displaying blockquote text fallback links instead.

 Behavior was replicated on test server with no plugins and default Twenty
 Twenty-One theme.

 Disabling iframe lazy-loading ([https://make.wordpress.org/core/2021/02/19
 /lazy-loading-iframes-in-5-7/ source]) remedies the issue and results in
 expected oEmbed post display behavior.

 **Windows 10**
 Chrome & Edge: WP post URL oEmbed blocked unless iframe lazy-loading
 disabled
 Firefox: unaffected

 **macOS Catalina**
 Chrome: WP post URL oEmbed blocked unless iframe lazy-loading disabled
 Safari: unaffected

 **iOS 14.4** Chrome & Safari: unaffected

 All browsers are latest versions.

 With default WP 5.8 treatment, ' loading="lazy" ' is appended to the WP
 post oEmbed iframe opening tag, and although the iframes appear in the
 page source code they do not appear on the rendered page. This seems to be
 tied to desktop browsers (Chrome and Edge on Windows, Chrome on macOS).

 This only seems to affect WordPress post URL oEmbed, as other sources of
 oEmbed links display correctly, such as YouTube and Instagram.

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Ticket URL: <https://core.trac.wordpress.org/ticket/52768>
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