Mobs turning fully invisible

Currently using this setup to equip my mobs then turn them invisible, but for whatever reason, they spawn correctly when I right click with an egg BUT if they randomly spawn or if the egg is throw they don't equip the items and just turn fully invisible. How can I fix this?

Skills:
- equip{i=playerghosthead:4} ~onSpawn
- equip{i=pghostchest:3} ~onSpawn
- equip{i=pghostpants:2} ~onSpawn
- equip{i=pghostboots:1} ~onSpawn
- potion{t=INVISIBILITY;d=2147483647;l=1} @self ~onSpawn