GarbageCollectionNotificationInfo has same information for before and after

FULL PRODUCT VERSION :
java version "9.0.4"
Java(TM) SE Runtime Environment (build 9.0.4+11)
Java HotSpot(TM) 64-Bit Server VM (build 9.0.4+11, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Darwin 17.3.0 Darwin Kernel Version 17.3.0: Thu Nov 9 18:09:22 PST 2017; root:xnu-4570.31.3~1/RELEASE_X86_64 x86_64

A DESCRIPTION OF THE PROBLEM :
I am seeing the same problem mentioned in:

 https://bugs.openjdk.java.net/browse/JDK-8027635

Only on java 9 (that bug was marked as fixed in 7u40). I do not see the problem when using java 8.

Some additional details at: https://github.com/Netflix/spectator/issues/502

REGRESSION. Last worked in version 8u172

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Change in amount used for G1 Eden Space after GC.
ACTUAL -
No change in amount used for G1 Eden Space after GC.

REPRODUCIBILITY :N
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
// This is from https://bugs.openjdk.java.net/browse/JDK-8027635

import java.lang.management.GarbageCollectorMXBean;
import java.lang.management.ManagementFactory;
import java.lang.management.PlatformManagedObject;
import java.util.ArrayList;
import java.util.List;

import javax.management.Notification;
import javax.management.NotificationEmitter;
import javax.management.NotificationListener;
import javax.management.openmbean.CompositeData;

import com.sun.management.GarbageCollectionNotificationInfo;

/**
 *
 */
public class NotificationTest {

  public static void main(String[] args) {
    for (GarbageCollectorMXBean bean : ManagementFactory.getGarbageCollectorMXBeans()) {
      addNotificationListener(bean);
    }

    List<String> strings = new ArrayList<String>();
    
    for(int i=0;i<10000;i++) {
      System.out.println(i);
    }
    
    System.gc();
    try {
      Thread.sleep(1000);
    } catch (InterruptedException e) {
    }
  }
  
  public static void addNotificationListener(PlatformManagedObject mbs) {
    if (mbs instanceof NotificationEmitter) {
      NotificationEmitter emitter = (NotificationEmitter)mbs;
      emitter.addNotificationListener(new NotificationListener() {
        @Override
        public void handleNotification(Notification notification, Object handback) {
          String notifType = notification.getType();
          if (notifType.equals(GarbageCollectionNotificationInfo.GARBAGE_COLLECTION_NOTIFICATION)) {
            // retrieve the garbage collection notification information
            GarbageCollectionNotificationInfo info = GarbageCollectionNotificationInfo.from((CompositeData)notification
                    .getUserData());
            System.out.println(info.getGcInfo().getMemoryUsageBeforeGc());
            System.out.println(info.getGcInfo().getMemoryUsageAfterGc());
          }
        }
      }, null, null);
    }
  }

}
---------- END SOURCE ----------