I recorded the game and watched OU's last sequence (in slow motion) at least 20 times now, and I was going to comment on this very thing. Reaves caught the ball square and went up straight, but then leaned/fell to the side as/after he let the ball go, as if he was trying to get fouled. I'm sure some momentum was involved, he had two guards running at him, and I can see wanting to get fouled, but he squared himself before going up and started to lean at the end of his shot.
FWIW, Reaves caught the ball with 8.5 seconds left and the ball left his hands with 7.9 left. Teague was between DH and the basket and was fairly square when DH crossed over toward Reaves. Manek was at half-court when DH saw Reaves and got ready to pass the ball. DH couldn't see Manek with a guard and big between them (i.e. behind DH), and there's no way DH is pulling the ball out in that situation when Reaves was wide open. The only way to get the ball back around to Manek was for Reaves to pass it back to DH in mid-air (which is when DH got open again), so DH could swing it back around to Manek. In a half-court set that might happen, but not at the end of the game on a fast-break after a steal when you're trying to win the game on the road.