I saw this situation in the NFL game between the San Fransisco 49ers and the Seattle Seahawks on December 15th, 2022 in which it happened in the 4th quarter at 13:19.
Seahawks punted the ball at SF 44 and the 49ers didn't catch it. I understand this situation is a fair catch so that the 49ers can start from that spot. But the ball rolled on the ground toward the end zone and the Seahawk picked up the ball right before it went through the end line. So it is recorded as a 43-yard punt, and the 49ers should have to start from their 1-yard line. If the Seahawk did not touch the ball, the ball would have gone through the end line, so it should be a touchback to start from the 25-yard line.
I didn't understand
- why the Seahawks can pick up the ball they punted
- why it is not the Seahawks' ball as in an onside kick situation,
- and why that situation is neither fair catch nor touchback.
Maybe I am misunderstanding some NFL rules.