FallingSand spawner spawn only sand

The "Tile" NBT tag has no impact on what block spawns, and neither does the "Data" tag. The spawner will only spawn sand, regardless of whether it worked in previous versions or not. Backdating causes the spawner to work as normal.

confirmed, I had this since 13w06a there's probably something changed in the way NBT works for falling blocks.

See comments in MC-9259.