Now the little guy is shocked but as I said he thinks he is bigger then he is so he attacks John. As expected from a guy names John Wayne he shacks of the attack like it was nothing. He lifts his spear and strikes the kobold with a flash of martial power the likes few could match. Now are kobold friend is not too bright but he is fast he thinks he might have a better shot if he shift over one square. Now John can only hit him once so he swings with another AO.
No, he doesn't... Polearm Gamble only triggers when an enemy shifts from a non-adjacent square to an adjacent square. The shift the kobold just made was from one adjacent square to another adjacent square - no Polearm Gamble.
Let's rewrite your scenario very slightly: "He lifts his spear and strikes the kobold with a flash of martial power the likes few could match,
and then shifts back one square. Now are kobold friend is not too bright but he is fast he thinks he
can shift forward one square to get close enough to attack."
Okay,
now, when the kobold shifts, he is moving from a non-adjacent square to an adjacent square, which is the requirement for Polearm Gamble.
Let's look at that "No Opportunity Attacks" text: "If you shift out of a square adjacent to an enemy, you don’t provoke an opportunity attack."
Okay - he's not shifting out of a square adjacent to an enemy, so this doesn't apply.
How about the "Moving Provokes" text? "If an enemy leaves a square adjacent to you, you can make an opportunity attack against that enemy. However, you can’t make one if the enemy shifts or teleports or is forced to move away by a pull, a push, or a slide."
Okay - he's not leaving a square adjacent to John, so again, this paragraph doesn't apply.
So we have Polearm Gamble saying John gets an OA, a line from the Shift description that doesn't apply, and a paragraph from the OA description that doesn't apply. Since they don't apply, the only rule we have is Polearm Gamble saying John gets an OA.
-Hyp.