Defender Bug: Invincible Soldiers >.<

Hi, I’m making a defender type game and I’ve come across a bug that I cant figure out. I think the problem lies in how I am adding or removing the enemy soldiers. The problem is that some of the soldiers are invincible and the arrows aren’t removed as they hit the soldiers while the rest of the army will die normally(also the arrows being removed as they hit the soldiers). I’m not getting any run time errors or any compiler errors.