Armorstands are not killable at all in adventure mode, even without the invulnerable tag.
1. /summon ArmorStand ~ ~ ~ {Invulnerable:0}
2. Hit it
Linked issues
Comments 2
Indeed a WAI. MC-71557
MC-75351
Armorstand not killable in adventure mode
Resolved
Duplicate
0
Logstone
(Unassigned)
Unconfirmed
Minecraft 1.8.1
Retrieved
Probably WAI, like paintings and Item frames.