I have the same problem with this quest. :x The "Royal Crowne" recipe doesn't show up at all in the cask when the task shows up to brew it, and shift+ctrl+clicking the task to make it go away results in the "serve royal crowne" interaction on both the advisor and servant remaining stuck until the "end" of the quest. And by that I mean I get to the illustration of the exploding ship and after closing it the quest just won't end. Several sim days go by with nothing happening. I know I don't have any mods that affect recipes, and apparently the autocompletequest cheat was removed from the game with one of the patches, nor did emptying my caches fix anything. I just don't know what to do other than avoiding this quest altogether. :/

I wonder if perhaps part of the problem in getting this quest to end, lies in what drink you're serving from the cask. I'm aware we're all brewing the correct drink, but the first time I played through this I chose to serve the advisor and servant the tampered drink from the cask. When the quest should have ended they were invisible on the docks with their map tags still showing, and both tags still showed the "serve potent royal crowne" tool tip.
I reloaded from a previous save (which luckily was just as my king should have been selecting what to brew), and noticed the tampered drink is actually reapers scythe, and not potent royal crowne, so the second time I chose the standard "serve drink", and the quest ended normally.
I think maybe the games recognizing that you served a drink regardless of what that drink is, till it should end and it then picks up you've still to serve the correct drink but by then it's too late??? Seems a little odd to check at the end after it's okayed the interaction, which makes me wonder if the quest ending from the back up kingdom was just luck, but it's also odd that they hang around invisible on the docks with that tooltip after I served them both the wrong drink.
Can people whose quest didn't end confirm whether they used serve drink, or serve tampered drink, if you still remember. It would be nice to have an answer to at least one of the quests that won't end for a large number of people.