It started few weeks ago I think, a bit annoying.. is it on purpose or a bug?

I've getting the same issue. There's a banner at the top of the page and a long list of recommended pages below the footer. However, the ads disappear when I switch to the desktop version of the site.

Same here, it just randomly popped up one day. I dislike using the desktop version of the site on mobile because well, there's just so much more to zoom in on.