In the first batch of Dark Brotherhood contracts, killing Ennodius Papius won't update his contract quest. The marker just stays above his dead body

I'm level 49, and i've tried to do this a few times since i was level 46, each time having to reload a save and carry on with other things, hoping something might trigger the quest to un-[censored] itself
But so far nothing..

I don't really want to have to say goodbye to 150 or so hours of gameplay because of this.
And it looks like the patch hasn't helped none either

Anyone else had this glitch?