Dragon Rider PQ: 1st Boss Glitch

On day 1, I went on a 3 person run with 1) myself a 13x Evan, 2) DrK, and 3) Shadower. My 2 party mates died on a DR. While they were gone, I kept attacking and the boss glitched. He stayed there until we killed it. The Shadower and the DrK were both not on the map when it glitched.