Symfony ContainerBagInterface implements Psr\Container\ContainerInterface but actually it returns a container parameter, not a service.
However ContainerInterfaceUnknownServiceRule checks for service existence, not parameter. For example this code
/** @var \Symfony\Component\DependencyInjection\ParameterBag\ContainerBagInterface $params */
$parameterValue = $params->get('parameter_name');
results in the following error
Service "parameter_name" is not registered in the container.
I suggest to ignore subtypes of ContainerBagInterface in the ContainerInterfaceUnknownServiceRule. Is this correct?