Hmm...odd. It's clearly the right spell and all the entries line up. At first glance I have no idea why it would show as "unknown".
For future reference, all crafting devices of a given type will all show the same thing, so there's no reason to run around to different craft halls to verify a recipe issue. They all load from a central database when the module starts, so if one has a problem, they'll all have a problem.