Well, FWIW, I can successfully reproduce this.

- Install https://chrome.google.com/webstore/detail/djflhoibgkdhkhhced... and flip to Android - or pull your phone out

- Go to https://m.youtube.com/watch?v=csD7BPEGAfA (note the m.)

- One of the links in the description says "Music by https://www.instagram.com/aquastoneth..." and points (literally) to "https://www.instagram.com/aquastoneth".

Hmm. I don't have any contacts, but I wonder if I can figure out where to send this...

You don't even need the extension, in Chrome just open dev tools, click the Mobile Emulation and choose a mobile device before going to m.youtube.com.

Very good point. I completely forgot about that.

YouTube is broken in other ways too. Just try a search for something a bit off the beaten path, sort by view count, and filter by videos. When I do this I get a lot of crap results back for many searches. For fun add in some qualifiers: OR (|), AND (+), and NOT (-). Or it'll say it got X number of responses, but if you actually go through all the pages at some point you'll suddenly get an empty page, and the result count will change to something completely different.

I'm astonished that YouTube has such glaringly obvious bugs.

I've noticed that bug too. It persists throughout mobile site and mobile apps.

That is a hilarious bug :D