when waterlogged stairs are next to flowing water on the side thats ''full block'' > where water doesnt flow out from, the waterflow animation is still triggerd in the waterlogged stairs.

and when there is a single blockspace between the watersource and the waterlogged stairs, the blockspace appears to become source. but its not really. and the waterlogged stairs still displays the waterflow animation. ( picture 2 outside of the encasing of stairs only on the marked block is watersource.