[Roberton3]

Not only was it 1st down, there's another point that never seemed to come up (with the announcers or other forums). What the heck does the rule book say? If whether the ball has crossed the plane of the goal line factors in to so many situations, why doesn't it come down to whether Ertz possessed the ball on top of the defender inside the plain. I know that you have to possess the ball and get one foot down typically. This particular situation was less common. Maybe I'm not thinking about this right, but what if Ertz possesses the ball entirely inside the planes and is on top of the defender? Not a TD?

I think the key is that if you catch a pass in the end zone, some part of your body needs to touch the ground in bounds after the catch.  So if you catch the ball, land on a defender (so you don't touch the ground) and then go out of bounds, it's not a touchdown.  It's the same as if you caught the ball in the air and got pushed out of bounds before coming down.  Under the old NFL force-out rule, there'd be no issue.  But college football doesn't have that rule.

[Roberton3]

Not only was it 1st down, there's another point that never seemed to come up (with the announcers or other forums). What the heck does the rule book say? If whether the ball has crossed the plane of the goal line factors in to so many situations, why doesn't it come down to whether Ertz possessed the ball on top of the defender inside the plain. I know that you have to possess the ball and get one foot down typically. This particular situation was less common. Maybe I'm not thinking about this right, but what if Ertz possesses the ball entirely inside the planes and is on top of the defender? Not a TD?

I think the key is that if you catch a pass in the end zone, some part of your body needs to touch the ground in bounds after the catch.  So if you catch the ball, land on a defender (so you don't touch the ground) and then go out of bounds, it's not a touchdown.  It's the same as if you caught the ball in the air and got pushed out of bounds before coming down.  Under the old NFL force-out rule, there'd be no issue.  But college football doesn't have that rule.