Rotation Issues With Spawners/Mob Type

So I cannot get spawners to work with - setrotation skill

The issue appears to be that they will not accept set rotation UNLESS they are an armor_stand, Here are 2 pictures of the set rotation working with armor stand, and not working with PIG. but I need it to work if it's a pig, I cannot use ARMOR_STAND because the 'guard' will not be able to use the look at players mechanic.

Little bit more investigation is, It's not just spawners, If you spawn the guard in

Like this /mm mobs spawn guardNPC_purple 1 newlobby,-208.330,51,232.494,210 Without a set rotation skill, It works

But if I spawn him like this /mm mobs spawn guardNPC_purple 1 newlobby,-208.330,51,232.494 With a set rotation skill, and no yaw value etc, It doesnt take the set rotation skill.