The explanation is simple. It is exactly the same explanation as 90% of the leaked reports: The information is wrong.
It is NOT POSSIBLE that this story is correct. And it has NOTHING to do with the Patriots, the Colts, or anybody who had contact with those balls.
EVERY. SINGLE. BALL. ever played with in the NFL, that was filled at room temp (~72°F) and then exposed for a long period (~90 minutes) to ~50°F air & ~46°F rain, will lose 1.5 psi of pressure.
(Note that Tom Brady took out the other 0.5 psi, by setting his preferred pressure to 12.5 psi, instead of the nominal 13.0 psi.)
EVERY ball on the Patriots side was down at around 11.0 psi. Every one.
EVERY ball on the Colts side was 1.5 psi below whatever value it was set to in the locker room before the game. Every one.
These are the "Gas Laws". Not the "Gas Suggestions".
Mother Nature allows No Substitutions.
Reporters can't get squat correct.
Do you have any reference to this? It's the first time I've heard anything about it.