diff --git a/services/core/java/com/android/server/notification/NotificationManagerService.java b/services/core/java/com/android/server/notification/NotificationManagerService.java
index 2c45fc8..73fc02c 100644
--- a/services/core/java/com/android/server/notification/NotificationManagerService.java
+++ b/services/core/java/com/android/server/notification/NotificationManagerService.java
@@ -82,6 +82,8 @@
 import static android.app.NotificationManager.zenModeFromInterruptionFilter;
 import static android.app.StatusBarManager.ACTION_KEYGUARD_PRIVATE_NOTIFICATIONS_CHANGED;
 import static android.app.StatusBarManager.EXTRA_KM_PRIVATE_NOTIFS_ALLOWED;
+import static android.app.backup.NotificationLoggingConstants.DATA_TYPE_ZEN_CONFIG;
+import static android.app.backup.NotificationLoggingConstants.ERROR_XML_PARSING;
 import static android.content.Context.BIND_ALLOW_WHITELIST_MANAGEMENT;
 import static android.content.Context.BIND_AUTO_CREATE;
 import static android.content.Context.BIND_FOREGROUND_SERVICE;
@@ -162,8 +164,6 @@
 import static com.android.server.am.PendingIntentRecord.FLAG_ACTIVITY_SENDER;
 import static com.android.server.am.PendingIntentRecord.FLAG_BROADCAST_SENDER;
 import static com.android.server.am.PendingIntentRecord.FLAG_SERVICE_SENDER;
-import static android.app.backup.NotificationLoggingConstants.DATA_TYPE_ZEN_CONFIG;
-import static android.app.backup.NotificationLoggingConstants.ERROR_XML_PARSING;
 import static com.android.server.notification.Flags.expireBitmaps;
 import static com.android.server.policy.PhoneWindowManager.TOAST_WINDOW_ANIM_BUFFER;
 import static com.android.server.policy.PhoneWindowManager.TOAST_WINDOW_TIMEOUT;
@@ -3069,7 +3069,7 @@
             migrateDefaultNAS();
             maybeShowInitialReviewPermissionsNotification();
 
-            if (android.app.Flags.modesApi()) {
+            if (android.app.Flags.modesApi() && !mZenModeHelper.hasDeviceEffectsApplier()) {
                 // Cannot be done earlier, as some services aren't ready until this point.
                 mZenModeHelper.setDeviceEffectsApplier(
                         new DefaultDeviceEffectsApplier(getContext()));
diff --git a/services/core/java/com/android/server/notification/ZenModeHelper.java b/services/core/java/com/android/server/notification/ZenModeHelper.java
index d5f13a8..31c9ea4 100644
--- a/services/core/java/com/android/server/notification/ZenModeHelper.java
+++ b/services/core/java/com/android/server/notification/ZenModeHelper.java
@@ -24,6 +24,8 @@
 import static android.app.NotificationManager.AUTOMATIC_RULE_STATUS_REMOVED;
 import static android.app.NotificationManager.AUTOMATIC_RULE_STATUS_UNKNOWN;
 import static android.app.NotificationManager.Policy.PRIORITY_SENDERS_ANY;
+import static android.app.backup.NotificationLoggingConstants.DATA_TYPE_ZEN_CONFIG;
+import static android.app.backup.NotificationLoggingConstants.ERROR_XML_PARSING;
 import static android.service.notification.Condition.SOURCE_UNKNOWN;
 import static android.service.notification.Condition.SOURCE_USER_ACTION;
 import static android.service.notification.Condition.STATE_FALSE;
@@ -44,8 +46,6 @@
 
 import static com.android.internal.util.FrameworkStatsLog.DND_MODE_RULE;
 import static com.android.internal.util.Preconditions.checkArgument;
-import static android.app.backup.NotificationLoggingConstants.DATA_TYPE_ZEN_CONFIG;
-import static android.app.backup.NotificationLoggingConstants.ERROR_XML_PARSING;
 
 import static java.util.Objects.requireNonNull;
 
@@ -303,6 +303,15 @@
     }
 
     /**
+     * @return whether a {@link DeviceEffectsApplier} has already been set or not
+     */
+    boolean hasDeviceEffectsApplier() {
+        synchronized (mConfigLock) {
+            return mDeviceEffectsApplier != null;
+        }
+    }
+
+    /**
      * Set the {@link DeviceEffectsApplier} used to apply the consolidated effects.
      *
      * <p>Previously calculated effects (as loaded from the user's {@link ZenModeConfig}) will be
diff --git a/services/tests/uiservicestests/src/com/android/server/notification/NotificationManagerServiceTest.java b/services/tests/uiservicestests/src/com/android/server/notification/NotificationManagerServiceTest.java
index cbfdc5f..828c1b6 100644
--- a/services/tests/uiservicestests/src/com/android/server/notification/NotificationManagerServiceTest.java
+++ b/services/tests/uiservicestests/src/com/android/server/notification/NotificationManagerServiceTest.java
@@ -43,8 +43,8 @@
 import static android.app.Notification.FLAG_USER_INITIATED_JOB;
 import static android.app.Notification.GROUP_ALERT_CHILDREN;
 import static android.app.Notification.VISIBILITY_PRIVATE;
-import static android.app.NotificationChannel.NEWS_ID;
 import static android.app.NotificationChannel.DEFAULT_CHANNEL_ID;
+import static android.app.NotificationChannel.NEWS_ID;
 import static android.app.NotificationChannel.PROMOTIONS_ID;
 import static android.app.NotificationChannel.RECS_ID;
 import static android.app.NotificationChannel.SOCIAL_MEDIA_ID;
@@ -78,7 +78,6 @@
 import static android.app.StatusBarManager.ACTION_KEYGUARD_PRIVATE_NOTIFICATIONS_CHANGED;
 import static android.app.StatusBarManager.EXTRA_KM_PRIVATE_NOTIFS_ALLOWED;
 import static android.app.backup.NotificationLoggingConstants.DATA_TYPE_ZEN_CONFIG;
-import static android.app.backup.NotificationLoggingConstants.DATA_TYPE_ZEN_RULES;
 import static android.content.pm.ActivityInfo.RESIZE_MODE_RESIZEABLE;
 import static android.content.pm.PackageManager.FEATURE_TELECOM;
 import static android.content.pm.PackageManager.FEATURE_WATCH;
@@ -336,12 +335,12 @@
 import com.android.server.wm.ActivityTaskManagerInternal;
 import com.android.server.wm.WindowManagerInternal;
 
-import com.google.android.collect.Lists;
-import com.google.common.collect.ImmutableList;
-
 import libcore.junit.util.compat.CoreCompatChangeRule.DisableCompatChanges;
 import libcore.junit.util.compat.CoreCompatChangeRule.EnableCompatChanges;
 
+import com.google.android.collect.Lists;
+import com.google.common.collect.ImmutableList;
+
 import org.junit.After;
 import org.junit.Assert;
 import org.junit.Before;
@@ -360,13 +359,15 @@
 import org.mockito.invocation.InvocationOnMock;
 import org.mockito.stubbing.Answer;
 
+import platform.test.runner.parameterized.ParameterizedAndroidJunit4;
+import platform.test.runner.parameterized.Parameters;
+
 import java.io.BufferedInputStream;
 import java.io.BufferedOutputStream;
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileOutputStream;
-import java.io.OutputStream;
 import java.time.Duration;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -375,9 +376,6 @@
 import java.util.concurrent.CountDownLatch;
 import java.util.function.Consumer;
 
-import platform.test.runner.parameterized.ParameterizedAndroidJunit4;
-import platform.test.runner.parameterized.Parameters;
-
 @SmallTest
 @RunWith(ParameterizedAndroidJunit4.class)
 @RunWithLooper
@@ -490,7 +488,8 @@
     private final NotificationChannel mParentChannel =
             new NotificationChannel(PARENT_CHANNEL_ID, "parentName", IMPORTANCE_DEFAULT);
     private final NotificationChannel mConversationChannel =
-            new NotificationChannel(CONVERSATION_CHANNEL_ID, "conversationName", IMPORTANCE_DEFAULT);
+            new NotificationChannel(
+                    CONVERSATION_CHANNEL_ID, "conversationName", IMPORTANCE_DEFAULT);
 
     private static final String PARENT_CHANNEL_ID = "parentChannelId";
     private static final String CONVERSATION_CHANNEL_ID = "conversationChannelId";
@@ -4262,8 +4261,13 @@
                     new NotificationChannel("foo", "foo", IMPORTANCE_HIGH));
 
         Notification.TvExtender tv = new Notification.TvExtender().setChannelId("foo");
-        mBinderService.enqueueNotificationWithTag(mPkg, mPkg, "testTvExtenderChannelOverride_onTv", 0,
-                generateNotificationRecord(null, tv).getNotification(), mUserId);
+        mBinderService.enqueueNotificationWithTag(
+                mPkg,
+                mPkg,
+                "testTvExtenderChannelOverride_onTv",
+                0,
+                generateNotificationRecord(null, tv).getNotification(),
+                mUserId);
         verify(mPreferencesHelper, times(1)).getConversationNotificationChannel(
                 anyString(), anyInt(), eq("foo"), eq(null), anyBoolean(), anyBoolean());
     }
@@ -4277,8 +4281,13 @@
                 mTestNotificationChannel);
 
         Notification.TvExtender tv = new Notification.TvExtender().setChannelId("foo");
-        mBinderService.enqueueNotificationWithTag(mPkg, mPkg, "testTvExtenderChannelOverride_notOnTv",
-                0, generateNotificationRecord(null, tv).getNotification(), mUserId);
+        mBinderService.enqueueNotificationWithTag(
+                mPkg,
+                mPkg,
+                "testTvExtenderChannelOverride_notOnTv",
+                0,
+                generateNotificationRecord(null, tv).getNotification(),
+                mUserId);
         verify(mPreferencesHelper, times(1)).getConversationNotificationChannel(
                 anyString(), anyInt(), eq(mTestNotificationChannel.getId()), eq(null),
                 anyBoolean(), anyBoolean());
@@ -7653,9 +7662,21 @@
                 .setContentTitle("foo")
                 .setSmallIcon(android.R.drawable.sym_def_app_icon)
                 .setStyle(new Notification.MessagingStyle("").addMessage(message2));
-        NotificationRecord recordB = new NotificationRecord(mContext, new StatusBarNotification(mPkg,
-                mPkg, 0, "tag", mUid, 0, nbB.build(), UserHandle.getUserHandleForUid(mUid), null, 0),
-                c);
+        NotificationRecord recordB =
+                new NotificationRecord(
+                        mContext,
+                        new StatusBarNotification(
+                                mPkg,
+                                mPkg,
+                                0,
+                                "tag",
+                                mUid,
+                                0,
+                                nbB.build(),
+                                UserHandle.getUserHandleForUid(mUid),
+                                null,
+                                0),
+                        c);
 
         // Update means we drop access to first
         reset(mUgmInternal);
@@ -15356,8 +15377,13 @@
         for (int i = 0; i < NotificationManagerService.MAX_PACKAGE_NOTIFICATIONS; i++) {
             StatusBarNotification sbn = generateNotificationRecord(mTestNotificationChannel,
                     i, null, false).getSbn();
-            mBinderService.enqueueNotificationWithTag(mPkg, mPkg, "testCannotPostNonUijWhenOverLimit",
-                    sbn.getId(), sbn.getNotification(), sbn.getUserId());
+            mBinderService.enqueueNotificationWithTag(
+                    mPkg,
+                    mPkg,
+                    "testCannotPostNonUijWhenOverLimit",
+                    sbn.getId(),
+                    sbn.getNotification(),
+                    sbn.getUserId());
             waitForIdle();
         }
 
@@ -16087,6 +16113,8 @@
         initNMS(SystemService.PHASE_SYSTEM_SERVICES_READY);
 
         mInternalService.setDeviceEffectsApplier(mock(DeviceEffectsApplier.class));
+
+        mService.onBootPhase(SystemService.PHASE_THIRD_PARTY_APPS_CAN_START, mMainLooper);
         // No exception!
     }
 
diff --git a/services/tests/uiservicestests/src/com/android/server/notification/ZenModeHelperTest.java b/services/tests/uiservicestests/src/com/android/server/notification/ZenModeHelperTest.java
index 0019b3e..c53fe95 100644
--- a/services/tests/uiservicestests/src/com/android/server/notification/ZenModeHelperTest.java
+++ b/services/tests/uiservicestests/src/com/android/server/notification/ZenModeHelperTest.java
@@ -49,6 +49,8 @@
 import static android.app.NotificationManager.Policy.PRIORITY_SENDERS_STARRED;
 import static android.app.NotificationManager.Policy.STATE_PRIORITY_CHANNELS_BLOCKED;
 import static android.app.NotificationManager.Policy.SUPPRESSED_EFFECT_BADGE;
+import static android.app.backup.NotificationLoggingConstants.DATA_TYPE_ZEN_CONFIG;
+import static android.app.backup.NotificationLoggingConstants.DATA_TYPE_ZEN_RULES;
 import static android.content.pm.PackageManager.PERMISSION_GRANTED;
 import static android.os.Process.SYSTEM_UID;
 import static android.provider.Settings.Global.ZEN_MODE_ALARMS;
@@ -84,8 +86,6 @@
 import static com.android.os.dnd.DNDProtoEnums.ROOT_CONFIG;
 import static com.android.os.dnd.DNDProtoEnums.STATE_ALLOW;
 import static com.android.os.dnd.DNDProtoEnums.STATE_DISALLOW;
-import static android.app.backup.NotificationLoggingConstants.DATA_TYPE_ZEN_CONFIG;
-import static android.app.backup.NotificationLoggingConstants.DATA_TYPE_ZEN_RULES;
 import static com.android.server.notification.ZenModeEventLogger.ACTIVE_RULE_TYPE_MANUAL;
 import static com.android.server.notification.ZenModeHelper.RULE_LIMIT_PER_PACKAGE;
 
@@ -102,6 +102,7 @@
 
 import static org.junit.Assert.assertNotEquals;
 import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertThrows;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyInt;
 import static org.mockito.ArgumentMatchers.anyString;
@@ -200,6 +201,9 @@
 import org.mockito.MockitoAnnotations;
 import org.xmlpull.v1.XmlPullParserException;
 
+import platform.test.runner.parameterized.ParameterizedAndroidJunit4;
+import platform.test.runner.parameterized.Parameters;
+
 import java.io.BufferedInputStream;
 import java.io.BufferedOutputStream;
 import java.io.ByteArrayInputStream;
@@ -219,9 +223,6 @@
 import java.util.concurrent.TimeUnit;
 import java.util.stream.Collectors;
 
-import platform.test.runner.parameterized.ParameterizedAndroidJunit4;
-import platform.test.runner.parameterized.Parameters;
-
 @SmallTest
 @SuppressLint("GuardedBy") // It's ok for this test to access guarded methods from the service.
 @RunWith(ParameterizedAndroidJunit4.class)
@@ -5332,6 +5333,22 @@
         mTestableLooper.processAllMessages();
 
         verify(mDeviceEffectsApplier).apply(eq(effects), eq(ORIGIN_APP));
+        assertTrue(mZenModeHelper.hasDeviceEffectsApplier());
+    }
+
+    @Test
+    public void testHasDeviceEffectsApplier_returnsFalseIfNotSet() {
+        assertFalse(mZenModeHelper.hasDeviceEffectsApplier());
+    }
+
+    @Test
+    @EnableFlags(FLAG_MODES_API)
+    public void testSettingDeviceEffects_throwsExceptionIfAlreadySet() {
+        mZenModeHelper.setDeviceEffectsApplier(mDeviceEffectsApplier);
+
+        assertThrows(
+                IllegalStateException.class,
+                () -> mZenModeHelper.setDeviceEffectsApplier(mDeviceEffectsApplier));
     }
 
     @Test