The company isn't commenting on the apparent leak, but it had talked about expanding mid-roll clips beyond live footage in early 2017.
You may not relish the thought of having to sit through even more ads, but this could be helpful in the long run. Publishers frequently limit their video selection on Facebook (or even avoid it altogether) because they make little if any profit. They're allowed to create sponsored videos, but they can't just inject ad spots and guarantee a relatively steady source of cash. If producers knew they could make an income from Facebook without special partnerships, you could see companies either posting more videos or, in some cases, posting videos for the first time.
And as Recode notes, mid-roll ads may sometimes increase the quality of the video you watch. That 20-second requirement would encourage publishers to create videos good enough to hold your attention for more than a brief moment. You won't necessarily see hard-hitting documentaries in your news feed, but you might see fewer hit-and-run clips with no real substance.