This is a temporary fix for the Issue Issue #11354
This module works only with Magento 2.2.4 version and need to be removed after upgrade/downgrade. Assumed that the issue will be fixed in the new release.
Run the following command in Magento 2 root folder:
composer require sashas/merged-css-issue
php bin/magento setup:upgrade
php bin/magento setup:di:compile
php bin/magento setup:static-content:deploy
Run the following command in Magento 2 root folder:
composer remove sashas/merged-css-issue
php bin/magento setup:upgrade
php bin/magento setup:di:compile
php bin/magento setup:static-content:deploy