Place the stairs like the picture provided (one sideways, one backwards) and then via the sideways stair the hitbox will be invisible in that one box.
MC-77981
Corner stairs have no hitbox
Resolved
Duplicate
0
Connor No
(Unassigned)
Unconfirmed
Minecraft 1.8, Minecraft 1.8.1, Minecraft 1.8.2-pre4, Minecraft 1.8.2-pre5, Minecraft 1.8.2-pre6, Minecraft 1.8.2-pre7, Minecraft 1.8.2, Minecraft 1.8.3
Retrieved
I believe that this is intended, but I cannot be sure. Try searching for issues that match this one. This issue might have been reported already.