I'm new to WvW but I know what I'm doing. I see these invaders just standing there while they are invulnerable to my hits. I ran up to one of the guys who looked like he was afk, and he killed me. I'm laying next to him and was looking at his boons, and noticed he has "Determined" on for 4 days. Invulnerable for 4 days... How does this happen?