While hunting shadow iron elementals today, I noticed this strange bug. Whenever my hit lightning triggered, the shadow iron elemental would take no damage from that hit or from the hit lightning. Hit fireball didn't cause this problem to happen when triggered. I will try hit flame arrow and hit harm later and report my findings here. On the screenshot below, you can see that the last two hits dealt damage, but the last one didn't as the hit lightning triggered at that particular hit.