If you have control before you break the plane, then if you break the plane it’s a touchdown, no matter what happens afterwards.
But if you are catching a ball in the end zone, and you don’t keep control long enough to be considered doing something “football-like” with it, it’s not a catch.
IN this case, the only reason it looked like a catch was because they ran it in slow motion. He didn’t have the ball under control long enough to do anything with it.
Still, it’s not a “bad” call, it’s just amazing to see them overturn the ruling on the field in a case where the slow-mo doesn’t really show you how little time he had both hands on the ball.
The defender kicked the ball out of his hand. That shortened the play. The guy had control just before the kick and over the end zone. Slow motion or not.