The balls that were used in the 2nd half were checked after the game and they hadn’t lost any air.
...which would demonstrate that they weren’t leaky. Doesn’t really address anything else by itself though. More waiting.
When they were checked and refilled with air at half time, if it was done outside, then the temperature was constant and air pressure would not decrease.
The balls never lost air, just air pressure.
Did you ever take a balloon outside on a cold day? Did it deflate on its own?