Imo, Pierce was no different in his play this game or game 1. The only difference is they threw him the ball. As has been pointed out numerous times, he's been open, but for whatever reason, he's not getting the ball.
As to why he got it this time, I can only assume the coaching staff emphasized it more pointedly or Minshew had some kind of epiphany either in his confidence in his arm or the fact that Pierce can catch the ball.