Expectations: When changing the attribute "generic.knockbackResistance" to base:1.0, it should make the mob not being affected by any knockback.

Bug: When a mob has the knockback resistance set to 1.0, it can still be affected by knockback from swords with the knockback enchantment on.

How to reproduce bug/how I found the bug:
1. Run the command "summon Witch ~ ~1 ~ {Attributes:[

{Name:generic.movementSpeed,Base:0.001}

,

{Name:generic.knockbackResistance,Base:1.0}

,

{Name:generic.maxHealth,Base:400.0}

,

{Name:generic.followRange,Base:20}

]}" in a command block.
You will then get a witch, with no movement, doesn't get affected by the knockback your fists deal, a health amount of 200 hearts, and follows players up to 20 blocks. So far everything is as it should.

2. Enchant a diamond sword with knockback 2, and hit the witch. The witch will now fly away a few blocks, which it shouldn't be able to do.

Final summary: Giving a witch full knockback resistance will still be bypassed by the knockback enchantment.