Others on reddit confirmed they’re seeing the same problem.

When I finally got someone from amazon on the phone, I was told that it was because their systems are starting to recognize the card number as Apple Pay, and amazon does not accept Apple Pay.

Huh. Mine was removed, too. No notification.

What the heck?

— Jason™ (@yuusharo) October 23, 2020

I experienced this on my iPad, but switched to my phone and had no problem

— Jeff (@carry_the_flag) October 23, 2020

I was just talking to them online and the guy said he could still see my card on his end.

— Travis Williams (@THE_ONE_TVW) October 23, 2020