When an honor/memorial tribute recipient designates an organization to receive acknowledgments, and that organization only exists as an organization relationship within that honor/memorial's constituent record, that organization's address will not print on honor/memorial acknowledgment letters generated through the Mail module. The solution is to make that organization a full constituent record, and link that record to the honor/memorial record. Since acknowledgees often have no connection to an organization, besides through the tribute, that organization may not qualify for full constituent record status as per business rules. This is true especially if they don't give a gift, and are not constituents by definition.