Permissions Issues With Some Wordpress Websites

[GrecoTechnology]

Describe the bug Some customer websites have permissions issues.

Wordpress > Tools > Site Health > Critical Issue

Background updates ensure that WordPress can auto-update if a security update is released for the version you are currently using.

Passed No version control systems were detected.
Passed Your installation of WordPress does not require FTP credentials to perform updates.
Error Some files are not writable by WordPress:
wp-includes/class-wp-styles.php
wp-includes/class-wp-user-query.php
wp-includes/l10n.php
wp-includes/date.php
wp-includes/php-compat/readonly.php
wp-includes/class-wp-oembed.php
wp-includes/images/w-logo-blue-white-bg.png
wp-includes/images/blank.gif
wp-includes/images/down_arrow.gif
wp-includes/images/spinner.gif
wp-includes/images/media/interactive.png
wp-includes/images/media/default.png
wp-includes/images/media/code.png
wp-includes/images/media/audio.png
wp-includes/images/media/text.png
wp-includes/images/media/archive.png
wp-includes/images/media/video.png
wp-includes/images/media/spreadsheet.png
wp-includes/images/media/document.png
wp-includes/images/uploader-icons.png

To Mitigate

cd /opt/domain.com/wordpress/_data/wp-includes
sudo chown -R www-data:www-data *

Expected behavior Files and folders should only have www-data ownership. Need to investigate what's causing these files and folders to change permissions.

[btmarouane]

Cannot reproduce this issue on a fresh install. Which websites have permission issues?