All fixed.
The problem was that the editor was converting the URL into a link before embedding the video. If your YouTube URL is showing up as a link, click the "Remove Link" button in the editor (it's the one with a red "X" over the image of a chain link), and that should do the trick.
The problem was that the editor was converting the URL into a link before embedding the video. If your YouTube URL is showing up as a link, click the "Remove Link" button in the editor (it's the one with a red "X" over the image of a chain link), and that should do the trick.