Yo it’s broken, can you fix?
It’s the WQ where we have to help make the wine at the vineyards; it simply just doesn’t work. Can’t get credit for jumping in the juice, the guy stops giving directions after three posts, and it just never completes.
I am the unhappy.
Unfortunately, nobody here in the CS forums would be able to fix it if it’s actually bugged.
First thing to do to make sure it’s not a UI or addon issue that’s blocking it from finishing is to do a Full UI Reset.
If it’s still not working, then you can submit an in-game bug report or maybe this will get moved over to the Bug Report forums for you 
I just hopped on an alt to test this as well, but unfo-- ah, Perl beat me to it. No surprises there!
In fact, there’s already a thread over there, so you can add your voice to it!
The WoWhead page for the quest has a dozen other people having the same issue with it.
Yeah I tried that and all - wasn’t the issue. I’ll see about a bug report - doubt it’ll be fixed anytime soon though so - kinda a moot point.
A large nature of players is to just claim something is broken without doing any troubleshooting, so it’s easier to just do it myself to corroborate before hitting up Google to find threads and just take it as hearsay. 12 players out of millions is a very, very, very miniscule control point in the grand scheme.
But as edited into my post, there’s already a thread in Bug Reports, so adding your notch to it will give them another data point to test and try to iron it out.