Not sure if its an intended change or not, but you used to be able to set crafting level on the stonecutting job so that you higher level crafter won't waste their time on it.
Hmm it's odd but yes, you cannot. I also noticed while looking that "Grand Sculputres" don't have the limits either.
I wonder if it's that you can't set the level on the highest-level-needed thing the work bench can do. Like for Art, if you can make Grand Sculptures you can make everything so why would you limit it based on pawn level?
Other than of course that you want the best possible grand sculptures so of course you'd want to limit it higher than the minimum so you don't waste all that jade but hey. Who am I to question this? :D
No clue when it changed. I very rarely set levels on things I'm not using specifically to train people, like my parka factories.
It's because it doesn't actually use a skill that way. There are other ways to manage who does the job, so I think this is really more of a feature request. Thanks for reporting, we may do this but it's not quite a bug.