The base router (`Magento\Framework\App\Router\Base`) ordering has been changed from 20 to 30 in Magento 2.2.2 at 2017-10-15

https://github.com/magento/magento2/commit/a688b66c

Magento 2.2.1

https://github.com/magento/magento2/blob/2.2.1/app/code/Magento/Store/etc/frontend/di.xml#L18-L22

Magento 2.2.2

https://github.com/magento/magento2/blob/2.2.2/app/code/Magento/Store/etc/frontend/di.xml#L18-L22

See also:

https://github.com/mage2pro/portal/issues/1