[MC-101553] FallingSand entity creates ghost blocks

When I use this command in a repeating command block, the corrosponding block turns into a ghost block.

/execute @a[team=blocks,score_blockID=2,score_blockID_min=2] ~ ~ ~ /summon FallingSand ~ ~-0.0099 ~

{Block:"minecraft:bookshelf"}

Notice that this doesn't happen to the other blocks that are not the same Block value.