Instead of using the web address that youtube shows when you publish the video go ahead and click the link and then copy and paste the url into the youtube tab above the reply box. Like this.
[YOUTUBE]https://www.youtube.com/watch?v=BBmS1gTKYvE&feature=youtu.be[/YOUTUBE
Add the "
]" back to the end of the above broken link and you'll have it.