Yeah, weapon kits have been working fine all this time. It’s just the legendary armor patch kits that have been mislabeled.
One would imagine that fixing this would be something as simple as swapping an item ID in a database defining the recipes available to a limited number of thralls. Of course, it’s still manual work that takes time that might be better spent fixing something more critical. After all, as soon as you can survive running the Unnamed City, running out of armor patch kits shouldn’t be an issue anymore (and until you can survive the Unnamed City, you’re hardly going to need legendary armor patch kits anyway).