Strange Death Message

I am making a mod that brings old creepypastas into Minecraft. The modding is 99% done, but I have run into one bug I am trying to figure out. Occasionally I will get a death message that reads: " death.attack.player.player ", and I have no idea why. My only guess is there is some visual bug when you use a shield to block a skeleton's arrow, for some reason it almost deals damage through the shield. There's no damage sound effect, and the player doesn't move. It's almost like I already took the damage, but the game needed to update, and the shield updates it. The issue is I believe if this damage update does enough to kill you, it gives you this death message. I haven't altered health, projectiles, or anything like that. For some reason, skeletons now just deal somewhere between 4 and 16 hearts of damage. Any ideas on what this could be would be greatly appreciated!