I've noticed that everytime the app is advertising "free shipping" after you add items to your cart the 'Discount' voucher suddenly disappears. It's happened more than once to the point that I can't ignore it. I am aware that shopee refreshes the vouchers so that users have 1 free shipping voucher per month and I'm sure that I haven't used mine yet. This kind of dishonest tactic is just disappointing to see.