Ender Dragon with maxHealth 0 plays death animation client-side but doesn't actually die

It only dies once the world is reloaded.

/summon minecraft:ender_dragon ~0 ~1 ~0 {Attributes:[{Name:generic.maxHealth,Base:0}]}

If you teleport to the summoned dragon you will see it is actually flying around. Reloading the world will make it play the death animation and it actually dies then.

/tp @p @e[type=minecraft:ender_dragon,limit=1]