He was judged to MAKE A FOOTBALL MOVE with CONTROL of the ball...
Watch the play again.
If this was in the field of play, I highly doubt Alexander would have spun and stretched for the end zone. It was CLEARLY a football move.
This play also happened last week:
If that is a fumble, then the Alexander play is a touchdown.
Hartline didn't even get to secure the ball before it was knocked out.