CUNY Academic Commons

I assume that means someone is pasting from elsewhere

Yes, I assume that this is the case. The HTML tags were written/pasted into the Visual tab, which means that they are encoded to `<` etc in the database and displayed as literal characters.

It's a bit surprising to see the divs, as opposed to the sort of HTML that one might manually write (like anchor tags). It seems like the kind of markup that might be generated by a program that converts raw text into HTML. But this does not appear to be the work of WordPress's, since its autop function uses paragraph tags rather than divs.

It may be worth following up with the original poster to see whether there's something the Commons can do to improve his posting workflow, but I'd say tentatively that there is no bug here.

We've taken steps in recent releases to mitigate the possibility of posting illegal markup, so I think we can close this for the time being.