Then it has a smaller capacity than a brand new battery should, but still larger than a heavily used battery. It's something the phone can report on, and android phones do. Apple can't guarantee your replacement battery was 'stored properly' either. All they can do is run their little programming tool to remove the warning regardless.

This scenario is completely outside the realm of 'new genuine Apple battery detected + no Apple warning reset = permanently harass the user with false warning'.

Let's be really clear here. The warning is 'unable to verify this iPhone has a genuine Apple battery'. Which is complete bullshit. The phone is perfectly aware that the battery is genuine because it carries a crypto signed identifier.