diff --git a/src/com/android/settings/network/telephony/NetworkProviderWorker.java b/src/com/android/settings/network/telephony/NetworkProviderWorker.java
index 464ee75cc7d..5205f5259ae 100644
--- a/src/com/android/settings/network/telephony/NetworkProviderWorker.java
+++ b/src/com/android/settings/network/telephony/NetworkProviderWorker.java
@@ -97,6 +97,7 @@ public class NetworkProviderWorker extends WifiScanWorker implements
 
     @Override
     protected void onSlicePinned() {
+        Log.d(TAG, "onSlicePinned");
         mMobileDataObserver.register(mContext, mDefaultDataSubid);
         mSubscriptionsListener.start();
         mDataEnabledListener.start(mDefaultDataSubid);
@@ -108,6 +109,7 @@ public class NetworkProviderWorker extends WifiScanWorker implements
 
     @Override
     protected void onSliceUnpinned() {
+        Log.d(TAG, "onSliceUnpinned");
         mMobileDataObserver.unregister(mContext);
         mSubscriptionsListener.stop();
         mDataEnabledListener.stop();
@@ -138,10 +140,11 @@ public class NetworkProviderWorker extends WifiScanWorker implements
     @Override
     public void onSubscriptionsChanged() {
         int defaultDataSubId = getDefaultDataSubscriptionId();
-        Log.d(TAG, "onSubscriptionsChanged: defaultDataSubId:" + defaultDataSubId);
         if (mDefaultDataSubid == defaultDataSubId) {
+            Log.d(TAG, "onSubscriptionsChanged: no change");
             return;
         }
+        Log.d(TAG, "onSubscriptionsChanged: defaultDataSubId:" + defaultDataSubId);
         if (SubscriptionManager.isUsableSubscriptionId(defaultDataSubId)) {
             mTelephonyManager.unregisterTelephonyCallback(mTelephonyCallback);
             mMobileDataObserver.unregister(mContext);
@@ -149,7 +152,7 @@ public class NetworkProviderWorker extends WifiScanWorker implements
             mSignalStrengthListener.updateSubscriptionIds(Collections.singleton(defaultDataSubId));
             mTelephonyManager = mTelephonyManager.createForSubscriptionId(defaultDataSubId);
             mTelephonyManager.registerTelephonyCallback(mHandler::post, mTelephonyCallback);
-            mMobileDataObserver.register(mContext, mDefaultDataSubid);
+            mMobileDataObserver.register(mContext, defaultDataSubId);
             mConfig = getConfig(mContext);
         } else {
             mSignalStrengthListener.updateSubscriptionIds(Collections.emptySet());
@@ -189,11 +192,13 @@ public class NetworkProviderWorker extends WifiScanWorker implements
 
         public DataContentObserver(Handler handler, NetworkProviderWorker backgroundWorker) {
             super(handler);
+            Log.d(TAG, "DataContentObserver: init");
             mNetworkProviderWorker = backgroundWorker;
         }
 
         @Override
         public void onChange(boolean selfChange) {
+            Log.d(TAG, "DataContentObserver: onChange");
             mNetworkProviderWorker.updateSlice();
         }
 
@@ -205,6 +210,7 @@ public class NetworkProviderWorker extends WifiScanWorker implements
          */
         public void register(Context context, int subId) {
             final Uri uri = MobileDataContentObserver.getObservableUri(context, subId);
+            Log.d(TAG, "DataContentObserver: register uri:" + uri);
             context.getContentResolver().registerContentObserver(uri, false, this);
         }
 
@@ -214,6 +220,7 @@ public class NetworkProviderWorker extends WifiScanWorker implements
          * @param context the Context object.
          */
         public void unregister(Context context) {
+            Log.d(TAG, "DataContentObserver: unregister");
             context.getContentResolver().unregisterContentObserver(this);
         }
     }