This happened either this or last week. I was on Dark Souls, and using an SL80 build to invade people in Anor Londo. I invaded a Dark Anor Londo world, and I was instantly thrown into the cutscene prior to the Dark Sun Gwyndolin boss fight. After the cutscene finished, I spawned where I normally do in Londo. About two minutes later, host entered the boss fight and kicked me out of his world. The odd thing is, when I left his world, I got the achievement for killing Gwyndolin. Not sure if this is a glitch or if host was using something to alter the game. Any ideas?