Mine slightly longer at 5 days for 5.5k, but considering that Maybank has been quite consistent, I'd like to think of it as a good start. Hopefully they don't screw this up, credit card benefits has been very very saddening these days.
Try to contact Shopee CS to see if they could help remove any "cache" or "failed attempts" to add the card for your Shopee account if there's any (to prevent system from detecting you already added the card, and left in pending state while you have not), then try again.

Could be Mbb server reroute fail as well..