[squiggleblaz]

I think it's more of a mobile-first design. It would be super weird to see it and do it with a mouse, but it's a common enough ui on mobile apps that I think a lot of people will be accustomed to it. But Instagram also has a feature where the second time you see a post that you haven't scrolled through, you see the second photo. This might server as a discoverability aid.

It is 153% the case that mobile user experience is almost entirely happened during the epoch when helping your user understand how to use the app rates second, and keeping some hidden features for expert users rates highly (the feeling of being a power user since you know some features others don't - making the user feel a little bit loyal to your app).

So if it's not perfectly discoverable, that's probable something the designers are happy with.