Debt collector asking to turn off Bluetooth to give card number vocally

My boyfriend has an old debt, he got a letter in the mail from Jefferson Capital with different payment options he could do or if he paid this certain amount right now the rest will be written off. on his credit karma he sees the debt there with Jefferson Capital, we called the number on the letter which was 844-880-9215, and while he was talking to the person they wanted him to turn off his Bluetooth to be able to say the card number over the phone and we thought that was so weird cause we heard that scammers do that. And we both worked for a bank for many years, and I’ve collected debt before but I wasn’t never officially a debt collector for my bank so I don’t even understand if they have a certain process. Everything looks legit though other than that number, though it could just be an internal number for that department and such, that isn’t given out to public unless for a reason like this but still. We are going to call the general number but I was just wondering if this is something debt collectors asked?