Making a Mob farm Is important and the block that is Important to have is slabs, slabs really needs to block the sight of mobs But in this case slabs are not doing anything like that, creepers and any other mobs can always See you outside even the Slabs is properly blocking the area of sight of a mob. Also slabs dont act like a half slab when puted on top of a 2 blocks high full blocks And Crouching below it doest work, i know that this is not a java Parity because slabs really needs to act like that.

Hoping for quickest action.