my friend had to follow up with HR. it took awhile for him to get it (this was like in 2018 and it was giftcard). their excuse for him was that the card (the one that all the etls signed) got wet so they had to ask for a new one, which took weeks to received. im not sure if that excuse sounds legit.
oh and the reason why he followed up was because he saw it listed on his paystub.