Buttons and non-full blocks do not prevent spiders from spawning

With todays release farms and non-spawn areas that utilize buttons will spawn spiders if any adjacent 1x1 block is unobstructed. The 2x2 spawn area of a spider seems to not be in effect anymore.

This is essentially a duplicate (images and description) of MCPE-153897

This can render many farms useless, and many areas that are spawn proofed for certain mobs dangerous.