Smooth Stone Slab uses its previous name - Stone Slab which is the same as regular stone slab.
MCPE-42390
Smooth Stone Slab uses wrong name
Resolved
Fixed
1
Confirmed in 1.11.0.3 on Windows 10.
Both the new slab with no border and the old slab with a border are called "stone slab" in the creative inventory.
In commands, the old slab is "stone_slab" and the new one is "stone_slab4" with a data value of 2.