I was doing BLM AF hands and when I talked to Guslam after getting the old gauntlers key item he tells you that he can't fix them. You then have to talk to the NPC @the shop which then tells you that you have to speak to Yin Pocanakhu @tenshodo. I've found that f you talk to the shop npc twice and it gives you the option to shop(brings up the shop menu) and then you go to Yin to trade the 1k she will not give you that option. You have to go back to talk to Guslam and the shop NPC (ONCE) and then talk to Yin. The quest breaks when you get the NPC shop menu. After lots of walking up and down in jeuno I was able to figure this out. Hopefully this saves people time.

That's interesting. I'll try to replicate this next time I do AF, which will be on BLM.