Yup, that’s intentional. It was actually a feature I requested. If the permalink changes all the time, then all external links to your vendors store wont work. So if your vendors say to a hundred people “Hey, here’s my store URL http://www.blah.com/vendor_stores/me” and then they change it, all those /me links are bad when the permalink changes costing you $$$. Updating the permalink, is the admin only method. 🙂
