Didn't I check that?
So I walked with her back to the apartment, put the key in, and turned it. Worked perfectly the first time. "I'm not sure what went wrong before, but it's working now," I tell her. She, and her daughter who's helping with the move, surprise me by asking me to stay while they check it, as thought they didn't just watch me successfully unlock the door with it. I stand there and... watch them each fail to unlock the door.
I unlock it for them again, and hand it back. They ask me, "Can we get a key that works?"
I say, "Let me check with the property manager," and head back to the office scratching my head. The next morning I stop by to explain my notes to him, and the trouble she had. He says, "Of course," and starts filling out a work order for a new set of keys to be made. I stop him and say, "Weren't you listening? The key works fine."
He tells me, "The key works... for you. You know how to turn a key. You push it in a tiny bit, and pull it out a tiny bit, as you turn it; without even thinking about it. You don't need a crisp new key. She does."