Re: The improbable improvement of Kareem Jackson
At 1:43 in the third, the DB was temporarily in-phase with the TE Davis but was not close enough to the side-line; he never turned his head to locate the ball.
At :54 in the fourth, Culliver played off-man and was ahead of the receiver Nelson along the side-line.
Here, as I said, the DB is in good position, and should turn his head to locate the ball.
He did just that.
As the ball was thrown inside, Culliver was able to deflect it.
If the ball was thrown as a back-shoulder fade, Nelson would probably have had a catch, but that's besides the point (I only mention this to show the double-edge sword of trying to locate the ball).