Invulnerable Iron Golems take damage with Windburst enchanted Mace

What I expected to happen:

   when bouncing on an invulnerable Iron Golem with a Wind Burst 3 Mace, I expected the enemy to not take damage.

What actually happened:

   Iron Golem took damage in 3 hits.

How to repeat:

   I summoned an Iron Golem using this command: /summon minecraft:iron_golem ~ ~ ~ {NoAI:1b,Invulnerable:1b}

   Then flew up like 5ish blocks and tried bouncing on the Golem