He looks less adventurous lately. To me it looks like he's been told to play a more conservative game after the injuries and support the midfield more.
Also in attack he's used to find Lingard with his permanent movement in central zones, and Martial is someone who picks the ball at his feet and is class at 'pass and move'. Rashford is a natural striker and has a tendency to find the back of defenders off the ball, Lukaku doesn't have much creativity and Alexis is just a shadow. So we are lacking that platform to keep and move the ball and we are forced to play more direct.
Against Palace I saw Pogba angry all the game, with gestures and bad faces and for me reflects that he's not comfortable in the last weeks. Today Southampton had the ball in some phases of the game and we were relying on counter-attack, with fast transitions and direct balls to the space.
Probably a bit of rest will do well on Pogba but I think he's mainly missing his friends, two of them to cover midfield and allow him more freedom, and the other two to make the football more dynamic and fluid. He has to be patient, there's no more.