Have had a couple of problems recently with delayed activation.
Last week went to buy a cricket bat at Rebel-I did what I usually do at the Mall and popped off to WW to buy Giftcard (triple points & 5%off). Came back and told it will take 24 hours for the card to be fully activated, Same thing happened in David Jones with a dress yesterday.
On both occasions they were able to keep the item behind for me so had/have to return. Have to go through the current parking schmozzle at the Mall twice in a row.
Haven't had problems with JB HiFi, Dick Smith or Myer giftcards in the past.