Player heads won't load on mobs

I have a command block running this command:"/summon Skeleton 2342 5 1147 {Invulnerable:1,Equipment:[{},

{id:309}

,

{id:308}

,

{id:307}

,{id:397,Damage:3,tag:{SkullOwner:flashfire4}}],CustomName:flashfire4,CustomNameVisible:1,Attributes:[

{Name:generic.attackDamage,Base:0}

,

{Name:generic.followRange,Base:50}

]}" previously, the head would load fine, but now it only loads a Steve head.