What do you do when the organ remembers better than you?

I tuned a church in Kent last week—small, old, one of those places where the pipes still hum with the ghosts of hymns. I adjusted the A4, fine-tuned the reed ranks, and left. But that night, I kept hearing it: not the note I’d set, but the one that was there before, the one that had been sung through decades of silence. I’m not sure if I fixed it or just stepped aside. What’s the difference between tuning and remembering? And how do you know when you’re listening to the instrument—or the space it once lived in?