Mobs spawned by command with armor do not receive armor.

When mobs (tested Zombie and Skeleton) are summoned, armor is not worn.
Command (generated by www.minecraftupdates.com/summon-command):

/summon Zombie ~0 ~1 ~0 {Equipment:[{Count:1,id:stone_sword,tag:{Unbreakable:1,ench:[{id:16,lvl:5}]}},{Count:1,id:chainmail_boots,tag:{Unbreakable:1,ench:[{id:3,lvl:4},{id:8,lvl:3},{id:2,lvl:4},{id:1,lvl:4},{id:4,lvl:4},{id:0,lvl:4}]}},{Count:1,id:chainmail_leggings,tag:{Unbreakable:1,ench:[{id:3,lvl:4},{id:1,lvl:4},{id:4,lvl:4},{id:0,lvl:4}]}},{Count:1,id:chainmail_chestplate,tag:{Unbreakable:1,ench:[{id:3,lvl:4},{id:1,lvl:4},{id:4,lvl:4},{id:0,lvl:4},{id:7,lvl:3}]}},{Count:1,id:chainmail_helmet,tag:{Unbreakable:1,ench:[{id:6,lvl:1},{id:3,lvl:4},{id:1,lvl:4},{id:4,lvl:4},{id:0,lvl:4}]}}],DropChances:[2.0F,2.0F,2.0F,2.0F,2.0F],ActiveEffects:[{Id:22,Amplifier:1,Duration:999999},{Id:12,Amplifier:1,Duration:999999},{Id:21,Amplifier:1,Duration:999999},{Id:8,Amplifier:1,Duration:999999},{Id:16,Amplifier:1,Duration:999999},{Id:10,Amplifier:1,Duration:999999},{Id:11,Amplifier:1,Duration:999999},{Id:1,Amplifier:1,Duration:999999},{Id:5,Amplifier:1,Duration:999999}]}

The screenshot attached shows the mobs that were spawned by the command. Also, when killed, no armor was ever dropped, and it still took the same amount of hits to kill as another mob with the same potion effects, without armor.