Hello. I've made a ticket to CDPR reporting this bug, and they were very considerate in their reply. I think they're aware of the bug, but I don't know if they were able to reproduce it properly. I guess the only thing left for me to do right now is cross my fingers and HOPE that they fix it in the next patch. Bug was introduced with the 1.10 patch, and wasn't fixed in either 1.11 nor 1.12 and 1.12.1.
I've tried everything, verifying game files with gog Galaxy, etc. etc. Nothing works

So I'm posting this like a shot in the dark: who knows? maybe someone else had the bug, and was able to fix it somehow, so any input would be welcome. CDPR forums are no help at all. People either don't reply, or don't care at all. So far I had only found one guy (which I haven't been able to contact) that has the same bug. He uploaded these couple of videos to youtube, which I'll be sharing the link. BOTH bugs happen towards the END of the videos (last 5 seconds), so be sure to watch it entirely. It basically involves the villagers who gives the quest to Geralt (in the 1st video, only the ealdorman) disappearing completely after Geralt approaches them (after the quest is concluded).

Anything like "Yes, I have the exact same bug, and I can't prevent it" is helpful ;) Thanks in advance!!

(exchange the hypertext in the links for them to work ;) )

youtube.com/watch?v=M9LqMNOVN2M

youtube.com/watch?v=e9qfnjWiDl8

If they can't reproduce it they're not aware of a bug, they're aware of a reported bug. They can't fix what they can't reproduce. Only according to you so far. This suggests it's a faulty installation, or a system problem. Or nobody else has ever seen such a bug. I can tell you that I have played in all of the patches you mention, and I've never seen such a thing.

It's not a faulty installation, I have re-installed multiple times, on different hard drives (all SSD drives)... System problem? NPC's vanish, and it may be a system problem? Well, I'd really like to hear some more about that...

I also haven't seen that bug BEFORE 1.10 (1.08, 1.07, 1.06, NONE of them had it). Have you tried reproducing it yourself (starting the sidequest from scratch), AFTER patch 1.10 (or 1.11 or 1.12)? You watched the videos, right?

I already answered that question. I would not have known what the hell you were talking about had I not, since you explained nothing, though did complain about forum users not caring.

That wasn't an explanation, that was a very vague rundown. You were right to post video links, because that told me nothing. I had nothing specific in mind, otherwise I would have said so in the beginning. It's possibly even a combination of things (inadequate system, configuration etc.) See, some quest givers, and even regular npcs, are scripted to disappear, even Ciri after you help her take care of some business in Novigrad -- stay around for a while afterwards and you will see her sitting with the elf guy, then eventually she just fades out. If this is happening prematurely you may get the effect seen in your videos. Where this would be in configuration files, though, I have no idea.

lol, yeah I was going to post the videos anyway... easier that way.

Very interesting what you said about the fading out of NPC's. I swear I haven't noticed anything like it (maybe one or another NPC, but not any quest related one), before this particular quest (one or another POP-IN of an NPC, which is the opposite, as you might know). I also noticed it's similar to the plants fading out, to stay out of the camera view... but nothing else.

So, if it's scripted, you think any modding to a particular script would prevent the bug?

Like I said, I have no idea where this is done. Perhaps ask back in the CDP forums?