When I use the command "/data merge block ~ ~-1 ~ {item:{id:diamond}}" on suspicious sand, it doesn't change the block data.

Steps to Reproduce:

1. Create a new world on 1.20 pre4.
2.  Place down suspicious sand.
3. Stand on top of the suspicious sand.
4. Use the command mentioned above.
5. While still on the suspicious sand, type in "/data get block ~ ~-1 ~" to get the block data.
6. You will notice that the block data didn't change if this affects all computers.

Notes: I remember this command working before.