Shoujo ai is not yuri bait, it can either be a story strictly romantic, no sex or hint of it at all, or it could be a platonic kind of love, it's often just soft romantic feelings mostly, between young girls o women which is literally the definition of "shoujo ai".
A yuri bait (queerbaiting) is when you are promise actual feelings, and not just a tease, is just to attract people that are into that without giving them what they want, and nothing more than that, often it does not even involve the growth of characters, and NOT EVEN the romantic feelings of each character are acknowledged, "they were just friends that you misunderstood"