When I did this command in the blue "Repeating" command block, /summon FallingSand ~ ~1 ~ {Time:1,Motion:[0.0d,1.0,1.0d],Block:stone}, It would do what its supposed to, but blocks would fall out as items, like you dropping stone out of your inventory, even when gamerule doTileDrops was set to false.
What happens with doEntityDrops? FallingSand are entities.