Rename Alder Tree Asset Without Ruining Lighting

Odd. I deleted the entire Terrain Assets folder, reimported it from a backup before the problem, and the messed-up lighting remains.

The lighting problem persists, even when I delete the Alder instance in the scene, and drag a new one in from the newly imported Terrain Assets folder, which has exactly the same contents as the backup before the problem. So it seems as though the Unity IDE itself has a problem.

Edit: Btw, I played around with some import settings, and the "messed-up lighting" is apparently identical to what happens when you check the "Swap UVs" checkbox on the Alder tree asset. Note that this, too, causes the same irrevocable change on the Alder tree's lighting.

Edit 2: Did some more testing. Apparently, you can only fix the problem if you overwrite the Library folder with a pre-lighting-problem backup AND rebuild the program rather than simply run it in Unity. THEN the Alder tree's lighting will return to normal. Only way I've found so far. (other than perfor$$anonymous$$g a complete backup, which is ultimately the same solution)