I have been playing the East Empire Company questline from the Bloodmoon expansion and up until now I was progressing through it quite smoothly
The issue is that:I cannot progress past the point of bringing back some Raw Stalhrim to Graring. Upon asking him about the Stalhrim when I collected a piece from the mine he did not take it from my inventory and instead gave me the same dialogue he did when he asked for a piece and gave me the Ancient Nordic Pickaxe.
I have avoided attacking him and he killed the assassin Coventina Celata without my help and he still agresses.
In an attempt to fix all of this I used an Amulet of the Thoughtful Pause which allowed me to get as far as I did but no further
I tried to kill Coventina but to my surprise Graring ganged up on me and attacked me as well.
I killed Coventina and he still agressed
I tried killing Coventina before she reached Graring but he happened to gang up on me again
The UESP Wiki and a google search yield no results. The questline is unplayable from that point on.