We don't know where that code comes from (!).
The only thing we did is copy-paste the iframe code from that particular video. For example:
Go to:
and then > share > copy iframe code and paste it into blog. That's it. This is code generated by Kaltura. And probably it created more code that blogs running on WP 4.7 don't like.
We only have problems with iframe codes generated by Kaltura. We have no problems with iframe codes from YouTube, Vimeo, etc.