Protect from assasins-quest not working

[Reskal]

Hi,

i met a lady in a tavern, needeing protection against assassins. She told me where she lives and that between 9 pm and midnight assassins will wait for her there. So i went to that place and a assassin appeared and i killed him. That was it. No message, quest is still in the log, and when returning to the questgiver in her tavern(The Bat and the Badger, its near map centre) she does not react. Returning to her house and waiting shows no other assassin.
After a certain time, somewhen next day the quest dissapears from the log and now i can talk again to the questgiver, she says she barely alived and i failed my quest.

I reloaded a former save several times and had 2 assassins coming but i died so i cannot say if the quest would have worked then.

Edit: i installed questpack 1, not sure if it has something to do with that, its a suggested mod.