MaxStrauss: I can't share your opinion, Time4Tea. I've played the game over the years on three different PCs and a laptop (less convincing). I never encountered any problems with this side quest: There's a precise instruction (-> Visit Cedric), there's a questmarker which brings you to the cave, and it's a
sidequest which you can solve or not. The partial poison resistance is nice to have, but not really necessary, and when you are fighting the Kayran and could profit by this potion then in most cases the game will be over soon. This means: You should avoid situations where you could profit by it: It's a bad emergency repair...
So don't blame the devs; there's nothing to repair.
Obviously you're entitled to your opinion, but we'll have to hard disagree on that one then. Issues that are apparent to me in my playthrough:
- it seems very unclear in the quest prompts that the ostmurk is not required to make the mongoose potion and that any ingredient that contains fulgur could be used.
- I made the potion without ostmurk and then found it in the cave afterwards. The ostmurk quest didn't resolve properly - at that point it was still telling me to find ostmurk. That is clearly a bug (possibly specific to the order in which I chose to do things).
- as discussed above, there is also confusing wording in the kayran quest prompt that makes it seem as if you can take on the kayran without Sile.
- this thing about the mongoose potion giving a permanent benefit to Geralt doesn't seem to be mentioned anywhere in the game, does it? I wouldn't have known anything about it if you hadn't told me. Hang on, does the potion give the permanent boost without the ostmurk, or only if you use it as an ingredient?
Imo, that (admittedly small) section of the game is sloppily designed and quite confusing, which is totally on the devs.