Affected Versions:

Nightly 98.a1, Beta 97 and Release 96

Tested on:

MacOS 11.6
Windows 10

Preconditions:

browser.search.region US,CA
extensions.formautofill.addresses.enabled true
extensions.formautofill.supportedCountries US,CA
download latest Firefox Nightly with region locale
have a complete address already saved in about:preferences#privacy

Steps to reproduce:

1. Reach the address form on ebay.ca
2. From the "Country or region" dropdown, select a different country.
3. Using the autofill feature, select 1 saved address entry.

Expected Results:

All the fields should be successfully autofilled.

Actual Results:

The fields are not auto-filled, are empty, even though the specific yellow highlight is done.

Notes:

Severity: S3 severity.
Reproducible on Chrome: No.
If the Country field is not previously changed, the issue is not reproducible, and the fields are auto-filled.

Issue reproducible also on ebay.fr - on the latest Nightly 99.0a1 and macOS Big Sur 11.6.

Reproducible also on ebay.de, ebay.uk, and ebay.com - on the latest Nightly 99.0a1 and macOS Big Sur 11.6.

This issue is still reproducible in the latest Nightly build 115.0a1 (2023-05-26), the same behavior is still present.

I am also able to reproduce this on https://www.ebay.be/, using Firefox Nightly 132.0a1 (2024-09-19), on Windows 11.

The issue is still reproducible in Nightly 138.0a1 (2025-03-04). Note that the behavior is different based on the Country changed previously. If I change the country to US and then autofill the form, the phone number field is not autofilled. If I change the country to Austria then autofill the form, none of the fields are autofilled, as in the description. For a better understanding, please see the screen recording attached here.

I am still able to reproduce this issue using Firefox Nightly 138.0a1 (2025-03-23), on http://ebay.fr/, while the prefs extensions.formautofill.heuristics.detectDynamicFormChanges/extensions.formautofill.heuristics.fillOnDynamicFormChanges are set to true, on macOS 14. If I change the country and then attempt to autofill the form, none of the fields are autofilled.

I am still able to reproduce this issue on https://www.ebay.co.uk/, using Firefox Nightly 138.0a1 (2025-03-27), while the prefs extensions.formautofill.heuristics.detectDynamicFormChanges/extensions.formautofill.heuristics.fillOnDynamicFormChanges are set to true, on macOS 14. If I change the country and then attempt to autofill the form, none of the fields are autofilled, except for the Country dropdown.

Fixed by Bug 1960395.

As of Fx139 address autofill is supported in US,CA,FR,GE,GB by default. Changing the country value from a supported region (US,CA,FR,DE,GB) to another supported region during autofill works as expected.

Note: I have filed Bug 1962034 for any country change on which the whole form gets replaced (e.g. AT, BE), because the autofill functionality breaks for those.

I verified this issue and it is indeed fixed for US,CA,FR,DE and GB. Based on comment 10, I will mark this as verified and follow-up in the bug 1962034 for the rest of the regions.