Both Don Birschel (USA) and Kenneth Sequeira (Singapore) provided the same information about a potential joint issue that was released a couple of months ago by Armenia and Egypt, but two weeks apart. Stamps are celebrating the 30th anniversary of relationship. Armenia issued its stamp on April 12, 2022 while Egypt released its stamp on March 22, 2022.
The design is different but features the same items: pyramids, Cheops sphinx and the statue “Mother of Armenia”. They also bear almost the same text relative to the anniversary of relationship establishment. For these reasons, we can deduce that both postal administrations communicated to create this pair of stamps. Even if the dates of issue eventually differed slightly and the design is not quite the same, we have to consider these stamps as joint, more precisely as Concerted [C] with the sub-type C3 (see Catalogue Vol 1 page 14 for detailed explanations). Catalogue Volume 15 will be updated accordingly with a new entry numbered [C20220322]. Thanks Don and Kenneth for this discovery.