Invisible Fairgraves

Joined a group today who had talked to fairgraves and had his quest, I joined halfway through and we got the allflame. Got back to fairgraves and they talked to him and then started fighting thin air (was pretty funny btw) but they were actually fighting him and minion skeles. Then boom they killed him and I finished the quest and all was well.

I have screenshot details if you need (pain to upload everytime):

~lvl48 shadow, merciless difficulty


Also had a repeated crash in a group doing fellshrine, guy said whenever pierce was used around him we crashed, happened 2 times then I gapped it. Same char, shadow ~ lvl50, lightning arrow build