Module config not saved, "Password reset form email address only description cannot be longer than 128 characters …"

I'm unable to reproduce this issue. can you test it in a fresh installation?

I tested the issue on several fresh and clean installs — with german locale, issue is always occuring.
Just use this DDEV recipe:

mkdir testsite-german && cd testsite-german
ddev config --project-type=drupal10 --docroot=web
ddev start
ddev composer create drupal/recommended-project:^10
ddev composer require drush/drush
ddev drush site:install --account-name=admin --account-pass=admin --locale=de -y
ddev launch
ddev composer require 'drupal/mail_login:^4.0'
ddev drush pm:enable mail_login  
ddev launch $(ddev drush uli)

Same problem for me, also german locale.

What I noticed: The field from the error edit-mail-login-password-reset-email-only-description is set to display:none, I don't know why. Seems that the german translation for the field is too long, but since we can not see the field, we can not fix it via the UI.

When I manually show the field, the error says: Password reset form email address only description cannot be longer than 128 characters but is currently 132 characters long.