Amex inquiring about my bank accounts for Cobalt application

Hi so I recently applied for Amex Cobalt card. I’ve already been using the Green card for a year. Today I received a call from a number claiming to be from Amex and that they’ve received my application but need to verify info. They asked me for my birthdate and complete address. Then asked if I have any other bank accounts other than my primary account. They wanted names and they would call one of them to verify I am banking with them and have credit card with them.

I felt a weird at this stage. I never had anything like this during my first Amex application. Is this normal procedure? Anybody else experienced anything like this?

I declined to provide them information over the phone and requested an email communication be sent to me. Apparently they will send me an email with a link for me to upload my recent utility bill or bank statement from another bank.

Any feedback or insights will be really helpful. Thanks!

UPDATE: I called Amex and they connected me to the department and confirmed the call was from Amex. But sadly they can’t do anything now as the file is in processing. Just gotta wait and see.

Thanks for all the responses!