Wallter was supposed to die,now unless you can pick his pocket it's dead.
Anyway it's another one that needs to be fixed.

i have the exact same problem. I manged to open the door he is knocking on, so now he is just knocking on air

exactly the same issue that I am having as well, pretty much identical. I have not even gotten the quest in the first place, I was just running around the city and I came across the man thumping on the door yelling 'let me in' and the witch hunters came and killed him. I looted the key but still nothing. Tried talking to the hunters but nothing. So I killed them and looted a letter off of them... still nothing, read the letter and then I got a quest. Its super confusing and I'm wondering where this quest actually starts and if I should bother trying to find it's origins and completing it?

That is where the quest starts.

I ran into the guy asking for help. He refused to speak to me, when the two witch hunters showed up I pulled my steel sword and attacked them manually, once they were dead, it triggered a cutscene where he gave me the key.

I ran into a second bug with this quest, when I was trying to get the last key from the corpse in the Bits. I find the corpse and search the area with my witcher senses, I find a red glowing torch bracket that I assume has something to do with the key but I can't interact with it, all I can do is ignite and put out the torch.

Edit: Nevermind, found the last key, but that torch bracket shouldn't be glowing.

I did what you did but never got any cutscene... gosh this is weird, I think its just messed up generally, I dont think I've done anything to make it broken.

Well, i certanly do not benefit from this patch at all, i had completed Novigrad:Closed City a long time ago and now from the completed section it moved it to failed for no apparent reason even tough all the objectives have a green tick on them, yeah thanks, soo far the only bugged quest I HAD was Scavanger:Viper Scholl (Level 6) where i somehow got punished for being a hero and killing the wraith at lvl 3 (if you remember she is lvl 7) looting the tomb, then having the dreadfull manner to close the cell door behind me, permanently locking myself out of that tomb and not being able to complete the quest that demanded me to return.Now this patch 1.05, i deeply regret looking forwad to it, has added some wooping game breaking errors such as infinite loading screen, dropping frames like flies , tough by how much i cannot say since i do not use any fps tool, still, i am able to tell because i went from screen tearing fps in some places (over 120 - high all with all post procesings enabled ) to sluggish, choppy, freezy (you name it) "motion"!

I wanna hear your thoughts on the manner,also if you have any informations about avoiding other glitches that this patch has brought, i'd be happy to hear them, don't have much time to play the game so it will matter to me at least. Thanks!

I was hoping this was solved. GUY IS STILL POUNDING ON THE DOOR. COME ON CDPR! FFS.