Affects Version/s: Minecraft 1.8.8, Minecraft 15w41b
Fix Version/s: Minecraft 15w45a
When there is a slab on a block and another on a second block(next to the first block) higher, the mobs can't jump from the first block to the second.
They can't even come by the side (picture 2).
They just stare at you.
The bug appears in all biome and in the nether too.