njs

What it says on the tin. With 1.22 nobody is realistically keeping their fat unrendered when it's objectively better to render them, so traders only dealing in unrendered fat basically means they aren't on the table for sale unless you specifically hunt for it to trade. I imagine this was just a small oversight where traders weren't updated to request the newly added rendered fat, because I can't think of any logical reason for this otherwise. I imagine this may get pushed to the wayside until 1.23, though I hope it doesn't. I do think there's probably enough bugfixes left for a 1.22.6 to be possible (I know some crafting recipes like hay to grass sometimes glitch out and don't allow you to craft unless you restart), but who knows.