Here’s my theory: His mojo was destroyed by YE Yang. He hasn’t won a Major since the Korean chased him down. After that, everyone in the field realized that Tiger wasn’t invincible. Even more importantly: Tiger knew he wasn’t invincible.
That photo says a lot.
You may well be right. I think it’s still a case of him not quite trusting his new swing as yet. It’s taken him 18 months to build it and maybe just doesn’t fully trust it in the heat of battle in a major championship.