So that's flat sawn with the heart side up. Moisture content is always changing in wood. The top got dried and the bottom may have picked up a little...
Edward's suggestion seems like the way to go, a magnet on one side only and a washer on the other. You can reduce the grip and the snapping noise by...
With your space limitations, maybe you can't have an aircraft carrier to land your planes on. A bench-centric shop may suit you better. Shrink the SS...