This has been happening to me for some time and I finally seemed to have solved it!
If your embed code uses the youtu.be domain, the plugin will not pick it up.
If you configure your embed code to use “enhanced privacy: it will use the
youtube-nocookies.com domain…and the plugin won’t see it. Simply delete the
“-nocookies” part of the domain and update your post/page.
Hope this helps!
