Is anyone else experiencing this issue, or am I just being paranoid about RNG? I’ve dedicated three weeks to slaying Spinmarrow, Invoq, and Kapraku in Zaralek Caverns, hoping to obtain the winding slitherdrake manuscripts for their hairy crest, white horns, and Heavy Scales. Unfortunately, luck has not been on my side, despite numerous attempts with three different characters. I even checked wowhead and discovered that others are facing the same problem. These manuscripts aren’t rare, low drop chance items like mounts, so it feels odd that it’s taking such a long time to obtain all of them. And let’s not forget the pain of taking down these bosses. They can’t be soloed, and to make matters worse, the Zaralek Caverns are practically deserted. The few players you do stumble upon don’t seem to have any interest in these rares anymore.
I believe Blizz deliberately nerfed the drop rate early into the patch since apparently they were dropping too often? Lmao. I’m so glad I got almost all of them before that. What a cluster f ZC is.
The only one I missed was kob’roks. Thankfully it eventually dropped after the nerf but it took freaking ages because of it. Blizz clearly nerfed the drop rates to the point that people have given up and abandoned ZC as their frustration became greater than the carrot that was meant to keep them there. Same with the toy off invoq that is currently bugged and no longer drops at all.
My only advice is to keep hunting the rare farming groups. There aren’t many anymore though due to how abandoned the zone is.
I feel your pain. Spinmarrow is the last ones I need for the slitherdrake. It’s really not fun trying to find people to help kill it, so I only kill it once or twice a week on my paladin because I can solo it.
I wish that after a point, all the manuscripts could be bought from a vendor, or drop from multiple sources.
Oh well I guess im gonna have to keep doing them this way then, I sure hope we can solo them after next patch’s gear or im gonna be screwed with this
I also havent’ seen any drops. The only ones I’ve got are those that are available at the reputation vendor.
The last time I saw a manuscript drop from a Zaralek rare was weeks ago. All I want is the heavy scales from Kapraku. 
I’ve killed him a number of times since the patch, and I’ve seen nothing.
I know that after Blizzard changed how the Zaralek rares worked, they increased the change for the manuscripts to drop. So it’s just bad RNG you’re experiencing.
From my experience, manuscripts can be finnicky.
I’ve actually had to farm a few rare NPCs, back to back between spawns, to get the ones I wanted.
The shark-snout for the Proto-Drake, for example. Only a few NPCs dropped that one, so I had to go out of the way and farm it.
Yeah, this drop rate seems a little too low. I never experienced them overdropping, so if they did nerf it, I have no idea why. And I was on a rare kill rampage for the first month it was out.
Please buff them rates blizz!!
Same with the cavern racer purses.