Dont worry about it, its normal. Ever since I had DACA, i received card first, then a few days later the letter of approval stating (you will receive your card in the mail in 60 days lol 😂 its a bit backwards.
Currently the same thing happen again, got card ordered, then it said they mailed it, then they said USPS picked up the card (so which is it, they mailed it or they came to pick it up lol ) and yesterday i received the NOA approval letter. 🤷🏻♂️