If you take 0 damage from an enemy, view having enough damage resistance/specific damage resistance (ie to traps), doing a "parry", or beat the boss and are attacked, but have a shield, the shield will then break and deal one damage to you.
Steps to Reproduce
1. Have 100% DR, parry or be at the end of a level after beating the boss and get attacked with shield.
2. Notice how on a normal attack you take 0 damage, but your shield still breaks from this attack.