For smooth stone you have to put stone in a furnace. I think it's the same for others smooth blocks.
edit : I have tested this for quartz and sandstone and i can now confirm that you have to use a furnace. It's not a bug.
C'est pas un bug ça a toujours été comme ça.Sur Minecraft java tu peux augmenter la hauteur de ton monde plat, mais pas sur cette version.
I confirm this bug.
For smooth stone you have to put stone in a furnace. I think it's the same for others smooth blocks.
edit : I have tested this for quartz and sandstone and i can now confirm that you have to use a furnace. It's not a bug.