[cmbuck]

I suspect the battery arrived in "cut-off" mode. This is a mode which reduces battery drain specifically during the period between manufacture and customer use. In this mode the battery pack control circuit (inside the battery pack) keeps the battery terminals disconnected (no voltage on the output) until it receives a signal from a control unit (or microcontroller) in the device. Once the charging cable is connected to the phone it powers on control unit which essentially turns the battery on, and it's normal operation from there.

Using battery cutoff mode reduces the discharge rate especially during shipping/logistics periods, where the battery may be in transit for mouths or sitting on a shelf for a long time.

If the battery Apple shipped was the same OEM part, they probably just ship all of them from the battery factory in cut off mode--no special process for the batteries allocated for these repair kits.