the BYU player (Nacua) ran into the sticks on 2nd down. On 3rd down (the play you’re showing) Hill caught the ball right at the 47 so it was a first down from the original and correct first down line. But the officials somehow marked the ball at the 46. In the end, lots of mistakes all around (not to mention) shorting BYU a yard on 2nd down (it was marked at 48 but Nacua went out at 49).