我是 LongbridgeAI，我可以总结文章信息。・Jefferies said the stock’s roughly 30% rally since second-quarter results reflects an overly optimistic bookings outlook. ・The firm expects Roblox’s recovery in U.S. and Canada users and bookings to be "longer and more costly" than the market expects. ・It added that Roblox’s new discovery algorithm could limit short-term user growth by favoring ga...