I just tried to throw in a Red Ring of Death [Infused] that still had my agony infusions on it. The MF didn’t recognize it. Maybe it’s just the RRoD?
I had the same problem with my equipped infused Red Ring of Death and Bagh Nakh. But I had another infused bagh nakh with nothing in it that did show up, and I was able to attune that one. Extracting from the other Bagh Nakh made it show up in the forge the first time, but the second, when I went back with all my rings, it wouldn’t