This is another one that's been reported forever but has been forgotten about. The SL world quest recipes are all marked as "training recipes / unlearnable (15)", but for some reason the Leatherworking ones do not get filtered out. Other professions do seem to get filtered out correctly as far as I can tell.

From a quick glance at the code, it looks like the Leatherworking ones were done with a bubbleDown and the other professions were not, so I'm guessing the bubbleDown is the problem.