I have defeated two different Ur-Ghast in twilight forest. Neither of them dropped the Ur-Ghast trophy that allows you to move on to the next boss. I know it is dropping items because I have recovered the Epic Shader Grabbag from each one. According to the wiki the Ur-Ghast is supposed to spawn a chest where it initially spawned at with it's drop items but it has not done so either time. Because of this bug I cannot advance any farther in the twilight forest mod pack. Can I please get some help with this?