I’ve run into this before - last year I was booking flights domestically in Peru paying in soles because it was half the price of booking in USD. I managed to get two of them booked but ended up having to pay the third via a travel agency in USD because the LATAM site simply stopped accepting my USA credit card. I can’t know whether it was some arbitrary security measure or whether their system caught on to me trying to game it and denied me because of it, but they denied both my USA credit card numbers as well as my debit cards.
