Config exclude Drupal core feature doesn't work (Drupal 8.8.1)

In a Drupal 8.8.1 project I'm trying to exclude Devel and Webprofiler contrib modules configs from being exported while running drush cex command, for that I used the new Drupal 8.8.0 feature configs exclude by setting the array of excluded module in settings.local.php as bellow:
$settings['config_exclude_modules'] = ['devel', 'webprofiler'];
But the following modules configs are still exported into the sync directory:

• devel.settings.yml
• devel.toolbar.settings.yml
• webprofiler.config.yml

Any idea why this behavior occur?