NEDNSProxyConfigurationDidChange not called

I have a NEDNSProxyProvider implementation (iOS 12+ app) and the configuration is provided through MDM.

I want to intercept any change in the proxy configuration and following the documentation I've used the NEDNSProxyConfigurationDidChange notification:

//Proxy configuration changed, probably after an update from the MDM
NotificationCenter.default.addObserver(self,
                               selector: #selector(handleDNSProxyConfigurationChanges(_:)),
                               name: NSNotification.Name.NEDNSProxyConfigurationDidChange,
                               object: nil)

But apparently the notification isn't fired, instead, the proxy is restarted by the system calling the usual

override public func stopProxy(with reason: NEProviderStopReason, completionHandler: @escaping () -> Void)

and

overridepublicfunc startProxy(options: [String: Any]? = nil, completionHandler: @escaping (Error?) -> Void)

Is this the intended behaviour and the documentation is out of date or is this a bug?

Thanks

~Federico