I don't know if this a bug for sure, but it certainly seems like an unaddressed oversight of merged crafting. If this is an intended feature, it's an absurd one at that. In Hamlet, every SW character with character-specific items can obtain the means to craft them, barring Walani (unless Sea Shells get added to the Oddities Shop). And yet, they cannot. This is something I've been very outspoken about, and think should be fixed while this spree of bug fixes continues.
-Woodlegs literally starts with the materials to craft the Sea Legs, the Nautical Tab is present, and still he cannot craft his boat in Hamlet.
-Cloth is present in Hamlet, and the Lucky Hat yields all the other materials for itself, but you still cannot craft them.
-Cloth is present in Hamlet, but Warly still cannot craft the Chef Pouch.
Every other DLC character with character-specific items can craft them outside their own DLC. Wigfrid, Webber, Wormwood, you name it. This is partly due to neglect and partly due to poor balancing (necessary materials being limited only to SW until recently, or still, in the case of Walani.)
I'd also like to make the suggestion, if I could, to move the Lucky Hat to the Fashion Tab, since it is technically renewable in RoG as well, as you can acquire Cloth by deconstruction Cloth Sails, Life Jackets, Windbreakers, and Blubber Suits found in the X Marks the Spots.
Go to Hamlet as a SW character with character-specific items (or RoG, in the niche and technical case of the Lucky Hat), give yourself the materials to craft your item(s), and the oversight is self-evident, as you cannot craft them.