Witch farm spawning more mobs than just witches

The witch farm I made in a previous version is still spawning witches as well as skeletons, spiders, creepers and zombies.

What I expected to happen was only witches to be spawned in the witch hut's parameter since it was a listed fix.

What actually happened was witches as well as other mobs being spawned in the witch hut's parameter.

Steps to reproduce:
1) Make 2 witch pads within a witch hut's parameter
2) The pads should be at a light level below 8
3) Wait 25 blocks from the pads for mobs to spawn
4) Witness witches and other mobs spawn on the pads