Texas vs Cal near last play

[MD Longhorn]

I didn't want to start this one, as I have a dog in the hunt. I'm kind of surprised no one else did.

3rd and short, clock running down (1:30ish left), Cal RB breaks through the line and rushes for the score. Drops the ball as he's crossing the goal line, but the ball came out of his hand at about the 1 1/2 foot line, falls to the ground just past the goal line and rolls about a foot when it's picked up by a UT player, approximately 3 seconds after it was dropped.

On field ruling was TD.

Replay ruling was Cal ball on the 1 yard line.

We've seen these a few times (in fact, once in week 1, and again this past Saturday in the Ohio State vs Oklahoma game, but the replay official missed this one entirely). EVERY other time we've seen this, it's ruled a touchback.

I can think of no combination of rules which would give Cal the ball on the 1. What happened here, and what SHOULD it have been?