When attacking a mob (tested with zombies, chickens and endermen) while wearing a Thorns enchanted chestplate, the player is occasionally damaged.
Linked issues
is duplicated by 8
MC-30432
thorns dammages the user in 13w36B
Resolved
MC-30509
Thorns bug
Resolved
MC-30602
Thorns enchantment on armor causes user to take damage when hitting a mob
Resolved
MC-30617
Throns II damage affecting user not mobs.
Resolved
MC-30724
Whenever you wear a thorns enchanted armour, rather than mobs taking damage when they hit you, you take damage when you hit them.
Resolved
3 more links
Confirmed.