Treasure Hunts potentially generating the wrong block entity data

[JiFish]

Reported in #427

"ERROR Block at 248,71,6 is CHEST but has net.minecraft.server.v1_12_R1.TileEntityMobSpawner@3d7e99ac. Bukkit will attempt to fix this, but there may be additional damage that we cannot recover."

[sshipway]

I've seen this, but can't duplicate on demand. I think what's happening is that the spawner and an intermediate chest are placed in the same location on certain landmarks, resulting in a chest with 2 tile entities. I need to work through them all in turn to find out which one is responsible.

[sshipway]

this may have been fixed by #431 which ensures all chests are defined as Soft=False