If you add the same item to your cart, it combines them into the same line with multiple quantity, but this causes an issue in some cases. If "only giftable" is enabled on the item, it asks which user you want to gift it to each time you add it to your cart. However, by combining them into one line, it ends up only sending them to the last user you input. The same is true for the item's message. The workaround is to put one in your cart, checkout, and repeat. But this takes longer and a lot of users mess it up.