Just noticed that the old JavaScript plugin I was using on a few Google Sites now is just an empty space on the Chrome browser on Android phones. Others report the same thing on both Android and iOS browsers using the current JavaScript or iframe versions from https://developers.facebook.com/docs/plugins/page-plugin on a variety of hosting platforms. On my Android phone, all three plugin versions render as expected if the browser is set to "use the desktop site". So the issue seems to be caused either by the Meta backend failing to deliver what it should to mobile browsers or all these mobile browser types having undergone a change that renders them incompatible.

What's your experience?