Ok!
I have smithy on some of these cities that are making a profit. I don't know if it is just flavor text, but it says that smithy produces weapons and armors. No new or more weapons and armor on those cities for even more months. It is really strange and I think that this caravan stuff to change shops, if that's the case, it is bad design.
I want to buy 3 more Heavy Lancer Helmet and 3 more Bronze Lamellar Over Mail for my clan, They just dont appear in any of the Khuzait cities anymore