For this exhibition, 2 type of exhibition cards were issued. One was with the tag "Dikelolakan oleh: Persatuan Setem Malaysia (Philatelic Society of Malaysia)" (see Type B) while the other is without (see Type A). Both souvenir cards are different in size (the on with the tag is longer).
I have a full set of this souvenir card with each day cancellation. From 9 sept - 13 Sept, it is canceled with "F" cancellation while from 14 Sept - 24 Sept it is a normal cancellation (see Type B).
My set show that 9 Sept - 17 Sept are Type A card and 18 Sept - 24 Sept are type B card. It could be that Type A cards were sold out and thus Type B were printed to replenish the stock.