Just noticed this too. I believe the statue of liberty once gave +2 prod per specialist. Then they realized how ridiculously overpowered that was and fixed it like 2 years ago by HALFING the bonus it gives - wohoo (still a damn useful wonder)!
However when they/he (he, as I bet even at that early point no more than 1 person was working on CiV) just changed the wonder effect and released it for the patch without even testing it not even once once. If anyone tested the change THIS would not have gone unnoticed.
Do I sound frustrated? YES. Why? Because this little bug exists for AGES now. How is this possible? How can one buy games of this company in the future if they never ever fix not even the easiest to fix bugs?
Cosmetic only? Maybe. Cosmetics sell though. Them being nice and polished is a keypart of a finished well perceived product. And I wouldn't even be not surprised if it actually did influence badly how the governor puts workers on tiles or assigns specialists.