Thanks for the report. Fixed.
I was unable to find a proper image with the schedule on the SA wiki page and in the patch description they didn't provided it either.
Please check if the schedule is correct now.

Sorry, but I don't see Flawless Magical Black Stone in this design. What do you mean?

Thanks for the report. The description is taken directly from the game client. Please report it to the official support of the game, so they could fix it in the game. When it'll be fixed in the game - it'll be fixed on the site as well.

Место на карте указано верно. У изумрудной горы данного НПЦ нет.

Added the recipe. Thanks!

Thanks for the report! Added a recipe for it.

The one in your screenshot is a different NPC with a similar name: Dongdong.

Thanks for the detailed explanation. I too think, they are using some special formula for Blackstar gear, which not only modifies the base chance, but affects the calculation of the failstacks as well.

I've double checked the data and the chance seems correct. Maybe some modifier is applied to them for red grade weapons though. Do you have any screenshots with real chances?

Please report in-game bugs to the official support of the game. I can't help you with them.