You know, that is quite odd. The fact that early Jack touched, alot and he didn't later. That said, I absolutely loved the hair ruffle from 'The Shroud'. And the fact that he did it right there in front of God and everybody? Shows me he still isn't quite as distant from Daniel as he probably should be.
Compare that expression to the ones he has while he's hugging Daniel, first from 'Serpent's Lair' which was very public and 'Forever in a Day' which was very private. He doesn't seem to care who sees him hugging Daniel.