I don't think it's always been an automatic first down for defensive holding. It is in the NFL, but college....not sure.
What I do know is that personal foul penalties that happen during a play, even if they are away from the ball, are always, ALWAYS added to the end of the play. However, that apparently was not the case last night. I believe it was a face mask that Texas was called for away from the ball while they were on defense, but somehow, the officials decided that the yards would not be penalized.
Personal fouls, no matter when and where they happen, ALWAYS result in yardage penalties.