In a way, something similar happened when he played at Tottenham. I remember he had a somewhat decent start for Spurs because he was surrounded with the proper teammates. But when the team gradually experienced a transformation (either by settling from the injury list or signing/selling players), Paulinho became a useless squad player over time.
He's a weird-to-rate footballer, who has some utterly drastical changes of form, from being great to become a lost cause in a matter of a few weeks. He often has some huge momentum flows in both (overall) quality and time extension, if you know what I mean
That said, I'd probably lower his Form even more, to a 3. Probably Mentality has to be knocked down a bit as well. Set aside for his stamina and football instinct, I've never seen him as a player who has a spirited or deternined approach to the game in a consistent basis.