You mean CVV number (card security code)?

No, the bank card account number itself. It remembers the expiry date and the CVV number.

This is strange.

Does it happen on a specific website?

All websites that I have not registered my card with.

What country are you in? https://support.mozilla.org/en-US/kb/credit-card-autofill

UK. It never used to be a problem until recently.

I have a similar problem. When I mouse over the field to be autofilled, a drop-down menu indicates that the correct information is to be filled in. But when I click on it, the field is not filled in. Not my name, not the card number, not my address. . . nothing. Autofill seems to know my info, it just refuses to take the final step of entering it into the field boxes.

They might have messed something up. Can you report this bug on https://bugzilla.mozilla.org ? Thanks.