Sand/Gravel and Concrete can fall through torches, levers, vines, dead corals, paintings, tripwire hooks, redstone torches, signs and item frames.

Sand/Gravel and Concrete that are falling on every non opaque block is destroied and doesn't spawn any item.

As a result there is no way to get Sand/Gravel and Concrete as an item except of breaking it.

That Sand/Gravel and Concrete are falling through the blocks that were metioned aboven if also an Issue in the Java Version.