I just noticed that all Master Crafters let you buy stuff like recipes from them even if you don’t have their crafting discipline, except for the Master Jewelers. They only show this option if you actually are a Jeweler.
Noticed this when I had to buy a recipe for my Jeweler alt and I couldn’t. Luckily there is a workaround, in Divinity’s Reach (and maybe also in other cities besides LA) there are also Apprentices and the Apprentice next to the Master Jeweler does let you buy the recipes when you’re not a Jeweler. Still it’s something to look at and fix.