SiteAccess services state changes during the request lifecyle as it is matched during the beginning of the request life. This makes services that depend on it (e.g. ConfigResolver) not to have the proper instance/state (a new instance is created when siteaccess is matched).

Solution for this is to make it a synchronized service.

See http://symfony.com/doc/current/cookbook/service_container/scopes.html#a-using-a-synchronized-service