This bug is partially fixed. The only issue remaining is that if the autofill is triggered from the expiry date field, the card number field will display the wrong dropdown when it is already autofilled (the autocomplete dropdown is displayed instead of the Clear Form dropdown). See the screen recording attached here. All the fields are in the same frame and have the same origin.
Bug 1825371 Comment 4 Edit History
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This bug is partially fixed. The only issue remaining is that if the autofill is triggered from the expiry date field, the card number field will display the wrong dropdown when it is already autofilled (the autocomplete dropdown is displayed instead of the Clear Form dropdown). See the screen recording attached here. All the fields are in iframes having the same origin.