SOD server. I didn't take the quest but the quest is hidden by Questie. Also checked on Hardcore server, the quest shows up as usual.

What version are you on? I just downloaded latest (v9.1.0+) on a new character and none of them were "Hidden by Questie".
Try update to the version from this morning.

I just updated the newest version, created a new character on SOD server. The quest remain hidden. Hardcore and Classic Era is fine.

I see. We're gonna investigate further. Thanks for the report :)

Yeah this one is a real issue and I frankly have no clue how it happened.

It looks like quests 456 and 636 were in the SoM Phase 4 (Zul'Gurub) blacklist, so they would only become un-blacklisted in SoM once Phase 4 was reached. We copied the SoM blacklist data for SoD (while bumping those phase numbers quite a bit) since it's a safe assumption the rollout of those quests will all be the same.

However, all of the other quests in the ZG phase are in the 8000-8200 range of IDs. Quest 636 isn't even implemented, it's on our normal Questie blacklist to just always be blacklisted regardless of client version. As for how 456 slipped in there, my best guess is that someone maybe put [123] and [456] as examples for structuring the blacklist, and then someone must have accidentally uncommented that line instead of removing it entirely once real data existed.

Either way, yeah it was real and completely unintentional, sorry about that. Fixed in upcoming version.