Actually you have it backwards.. The ball was never in Mixon's gut..
Here is the sequence..
1) Mixon reaches out his right arm and tries to cup the ball.
But he never controls it..
You can see the ball already bouncing up off the turf even before Parsons gets his hands on it.
Then as Mixon tries to pull the ball in you see it bouncing up.. This is what they used to claim Dez didn't catch it because the ball moved when it hit the turf.
Then you see Parsons helping the ball move around by getting his left hand under it.
Then even more of the ball gets exposed as they wrestle for it.
https://twitter.com/ronnietee24/status/1571919124267139072/photo/4
So now you see Parsons is winning the tug of war as even more of the ball gets exposed. And Parsons' arm is now between the ball and Mixon's helmet.
https://twitter.com/ronnietee24/status/1571919824166572035/photo/1
I would say by this point Parsons has more control of the ball.. THe ball is cupped in his left arm against hsi chest while Mixon only had it sitting on his forearm.
https://twitter.com/ronnietee24/status/1571919824166572035/photo/2
This is the money shot to me.. Here you see that Parsons has rolled over to his side and now has the ball in HIS gut and Mixon is now trying to wrest it away from HIM.
https://twitter.com/ronnietee24/status/1571919824166572035/photo/4
WHich he actually does because when the unpile Parsons still has the ball in his gut.
https://twitter.com/ronnietee24/status/1571923005235933184/photo/1
Bottom line is the ball was never in Mixon's gut.. not in his control and the damn play should have been reviewed.