Still an issue in Bedrock, but the discussion and answer seems to lie in MCPE-19393. The tl dr is that the (unfortunate?) choice to use UWP makes this "working as intended".
I'm seeing this on a 1.18.12 Realms server consistently. It seems to be ignoring new lines completely.
This is still happening in v1.21.2 and is easily reproducible with sandstone stairs.