Seems they saw the submission and edited their response, appending the following:

    EDIT 2022-12-20: There are at least 3 cases where this is desirable within a short period of time:
    1. Filling password confirmation fields on the same page if we were not able to automatically do so.
    2. Filling the same password on the next page
    3. The password didn’t save on the change form so you need to fill it on the log in page.
       Bug 1551723 will give the user the option to choose a new password.

#1551723 tracked @ https://bugzilla.mozilla.org/show_bug.cgi?id=1551723