Nebraska v Oklahoma - OOB question

[kentref]

Saturday night's Big 12 Championship Game. I believe it was in the 3rd quarter and a Nebraska punt is downed at about the B 1 yard line. The A player downing the punt clearly stepped out of bounds inside the B 5 yard line and was the first player to touch the ball. The SJ/FJ that was right on the pylon didn't throw his hat so I'm guessing he didn't see the player step out of bounds.

Question: If the A player did go OOB voluntarily then his touching of the ball inbounds should be an illegal touching foul, 5 yards from the previous spot, correct?

Question #2: Could this play (the stepping OOB) be challenged and the ruling on the field overturned?