I don't know if this is something only on the TLP server (as I am noticing it there) but when I went to craft just items on the Sewing table in just the Artisian 4 book, a level 1 item came up, greyed out. Bug? Or a typo?
Confirmed that it looks the same on AB. Probably been that way for a long time, and no one has noticed. Just to clarify, the recipe does come from the level 4 recipe book (along with others), however the recipe for that particular item is a level 1 recipe, as where all the other items are level 4 recipes. In every case, the resulting item is a level 1 piece of gear, but the recipe itself should match the recipe book that it came from, so that you do get the appropriate amount of XP for crafting it.
