Water doesn’t fall

Water fails to fall/flow down when breaking a water logger bottom half slab...
Surround a bottom half slab with full blocks (do this a block or more in the air), water-log the half slab, then break the half slab and the water doesn’t fall/flow downwards.
I tested this in creative on my iPad and in survival on my bedrock dedicated server, it’s the same in both, the screenshot is from survival mode.