diff --git a/core/java/android/net/NetworkCapabilities.java b/core/java/android/net/NetworkCapabilities.java
index d2af023..0b92893 100644
--- a/core/java/android/net/NetworkCapabilities.java
+++ b/core/java/android/net/NetworkCapabilities.java
@@ -773,7 +773,7 @@
         // TODO: consider only enforcing that capabilities are not removed, allowing addition.
         // Ignore NOT_METERED being added or removed as it is effectively dynamic. http://b/63326103
         // TODO: properly support NOT_METERED as a mutable and requestable capability.
-        final long mask = ~MUTABLE_CAPABILITIES & ~NET_CAPABILITY_NOT_METERED;
+        final long mask = ~MUTABLE_CAPABILITIES & ~(1 << NET_CAPABILITY_NOT_METERED);
         long oldImmutableCapabilities = this.mNetworkCapabilities & mask;
         long newImmutableCapabilities = that.mNetworkCapabilities & mask;
         if (oldImmutableCapabilities != newImmutableCapabilities) {
diff --git a/tests/net/java/android/net/NetworkCapabilitiesTest.java b/tests/net/java/android/net/NetworkCapabilitiesTest.java
index e3b06c8..7346f9f 100644
--- a/tests/net/java/android/net/NetworkCapabilitiesTest.java
+++ b/tests/net/java/android/net/NetworkCapabilitiesTest.java
@@ -21,10 +21,14 @@
 import static android.net.NetworkCapabilities.NET_CAPABILITY_INTERNET;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_METERED;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_RESTRICTED;
+import static android.net.NetworkCapabilities.NET_CAPABILITY_VALIDATED;
 import static android.net.NetworkCapabilities.RESTRICTED_CAPABILITIES;
+import static android.net.NetworkCapabilities.TRANSPORT_CELLULAR;
+import static android.net.NetworkCapabilities.TRANSPORT_WIFI;
 import static android.net.NetworkCapabilities.UNRESTRICTED_CAPABILITIES;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotEquals;
 import static org.junit.Assert.assertTrue;
 
 
@@ -114,4 +118,45 @@
         assertFalse(netCap.hasCapability(NET_CAPABILITY_NOT_RESTRICTED));
     }
 
+    @Test
+    public void testDescribeImmutableDifferences() {
+        NetworkCapabilities nc1;
+        NetworkCapabilities nc2;
+
+        // Transports changing
+        nc1 = new NetworkCapabilities().addTransportType(TRANSPORT_CELLULAR);
+        nc2 = new NetworkCapabilities().addTransportType(TRANSPORT_WIFI);
+        assertNotEquals("", nc1.describeImmutableDifferences(nc2));
+        assertEquals("", nc1.describeImmutableDifferences(nc1));
+
+        // Mutable capability changing
+        nc1 = new NetworkCapabilities().addCapability(NET_CAPABILITY_VALIDATED);
+        nc2 = new NetworkCapabilities();
+        assertEquals("", nc1.describeImmutableDifferences(nc2));
+        assertEquals("", nc1.describeImmutableDifferences(nc1));
+
+        // NOT_METERED changing (http://b/63326103)
+        nc1 = new NetworkCapabilities()
+                .addCapability(NET_CAPABILITY_NOT_METERED)
+                .addCapability(NET_CAPABILITY_INTERNET);
+        nc2 = new NetworkCapabilities().addCapability(NET_CAPABILITY_INTERNET);
+        assertEquals("", nc1.describeImmutableDifferences(nc2));
+        assertEquals("", nc1.describeImmutableDifferences(nc1));
+
+        // Immutable capability changing
+        nc1 = new NetworkCapabilities()
+                .addCapability(NET_CAPABILITY_INTERNET)
+                .removeCapability(NET_CAPABILITY_NOT_RESTRICTED);
+        nc2 = new NetworkCapabilities().addCapability(NET_CAPABILITY_INTERNET);
+        assertNotEquals("", nc1.describeImmutableDifferences(nc2));
+        assertEquals("", nc1.describeImmutableDifferences(nc1));
+
+        // Specifier changing
+        nc1 = new NetworkCapabilities().addTransportType(TRANSPORT_WIFI);
+        nc2 = new NetworkCapabilities()
+                .addTransportType(TRANSPORT_WIFI)
+                .setNetworkSpecifier(new StringNetworkSpecifier("specs"));
+        assertNotEquals("", nc1.describeImmutableDifferences(nc2));
+        assertEquals("", nc1.describeImmutableDifferences(nc1));
+    }
 }