Created attachment 382016 [details]
Since updating Tech Preview from 2.26.1 to 2.27.2, YouTube videos are now transparent green overlaying content duplicated from elsewhere on the page. No video content is displayed. See attached screenshot.
This occurs both with and without the org.freedesktop.Platform.openh264 extension installed so it's not a problem with that.
*** This bug has been marked as a duplicate of bug 201422 ***