diff --git a/src/anki-integration/card-creation.test.ts b/src/anki-integration/card-creation.test.ts
index a89d58cb..0ca979c7 100644
--- a/src/anki-integration/card-creation.test.ts
+++ b/src/anki-integration/card-creation.test.ts
@@ -487,3 +487,88 @@ test('CardCreationService tracks pre-add duplicate note ids for kiku sentence ca
   assert.deepEqual(duplicateLookupExpressions, ['重複文']);
   assert.deepEqual(trackedDuplicates, [{ noteId: 42, duplicateNoteIds: [7, 18, 30] }]);
 });
+
+test('CardCreationService does not track duplicate ids when pre-add lookup returns none', async () => {
+  const trackedDuplicates: Array<{ noteId: number; duplicateNoteIds: number[] }> = [];
+
+  const service = new CardCreationService({
+    getConfig: () =>
+      ({
+        deck: 'Mining',
+        fields: {
+          word: 'Expression',
+          sentence: 'Sentence',
+          audio: 'SentenceAudio',
+        },
+        media: {
+          generateAudio: false,
+          generateImage: false,
+        },
+        behavior: {},
+        ai: false,
+      }) as AnkiConnectConfig,
+    getAiConfig: () => ({}),
+    getTimingTracker: () => ({}) as never,
+    getMpvClient: () =>
+      ({
+        currentVideoPath: '/video.mp4',
+        currentSubText: '字幕',
+        currentSubStart: 1,
+        currentSubEnd: 2,
+        currentTimePos: 1.5,
+        currentAudioStreamIndex: 0,
+      }) as never,
+    client: {
+      addNote: async () => 42,
+      addTags: async () => undefined,
+      notesInfo: async () => [],
+      updateNoteFields: async () => undefined,
+      storeMediaFile: async () => undefined,
+      findNotes: async () => [],
+      retrieveMediaFile: async () => '',
+    },
+    mediaGenerator: {
+      generateAudio: async () => null,
+      generateScreenshot: async () => null,
+      generateAnimatedImage: async () => null,
+    },
+    showOsdNotification: () => undefined,
+    showUpdateResult: () => undefined,
+    showStatusNotification: () => undefined,
+    showNotification: async () => undefined,
+    beginUpdateProgress: () => undefined,
+    endUpdateProgress: () => undefined,
+    withUpdateProgress: async (_message, action) => action(),
+    resolveConfiguredFieldName: () => null,
+    resolveNoteFieldName: () => null,
+    getAnimatedImageLeadInSeconds: async () => 0,
+    extractFields: () => ({}),
+    processSentence: (sentence) => sentence,
+    setCardTypeFields: () => undefined,
+    mergeFieldValue: (_existing, newValue) => newValue,
+    formatMiscInfoPattern: () => '',
+    getEffectiveSentenceCardConfig: () => ({
+      model: 'Sentence',
+      sentenceField: 'Sentence',
+      audioField: 'SentenceAudio',
+      lapisEnabled: false,
+      kikuEnabled: true,
+      kikuFieldGrouping: 'manual',
+      kikuDeleteDuplicateInAuto: false,
+    }),
+    getFallbackDurationSeconds: () => 10,
+    appendKnownWordsFromNoteInfo: () => undefined,
+    isUpdateInProgress: () => false,
+    setUpdateInProgress: () => undefined,
+    trackLastAddedNoteId: () => undefined,
+    findDuplicateNoteIds: async () => [],
+    trackLastAddedDuplicateNoteIds: (noteId, duplicateNoteIds) => {
+      trackedDuplicates.push({ noteId, duplicateNoteIds });
+    },
+  });
+
+  const created = await service.createSentenceCard('重複なし', 0, 1);
+
+  assert.equal(created, true);
+  assert.deepEqual(trackedDuplicates, []);
+});
diff --git a/src/anki-integration/card-creation.ts b/src/anki-integration/card-creation.ts
index ed9b8e5a..36d7a582 100644
--- a/src/anki-integration/card-creation.ts
+++ b/src/anki-integration/card-creation.ts
@@ -602,10 +602,12 @@ export class CardCreationService {
           log.warn('Failed to track last added note:', (error as Error).message);
         }
 
-        try {
-          this.deps.trackLastAddedDuplicateNoteIds?.(noteId, duplicateNoteIds);
-        } catch (error) {
-          log.warn('Failed to track duplicate note ids:', (error as Error).message);
+        if (duplicateNoteIds.length > 0) {
+          try {
+            this.deps.trackLastAddedDuplicateNoteIds?.(noteId, duplicateNoteIds);
+          } catch (error) {
+            log.warn('Failed to track duplicate note ids:', (error as Error).message);
+          }
         }
 
         try {
diff --git a/src/anki-integration/duplicate.test.ts b/src/anki-integration/duplicate.test.ts
index 5a258e90..1c8ab593 100644
--- a/src/anki-integration/duplicate.test.ts
+++ b/src/anki-integration/duplicate.test.ts
@@ -267,3 +267,33 @@ test('findDuplicateNote does not disable retries on findNotes calls', async () =
   assert.ok(seenOptions.length > 0);
   assert.ok(seenOptions.every((options) => options?.maxRetries !== 0));
 });
+
+test('findDuplicateNote stops after the first exact-match chunk', async () => {
+  const currentNote: NoteInfo = {
+    noteId: 100,
+    fields: {
+      Expression: { value: '貴様' },
+    },
+  };
+
+  let notesInfoCalls = 0;
+  const candidateIds = Array.from({ length: 51 }, (_, index) => 200 + index);
+  const duplicateId = await findDuplicateNote('貴様', 100, currentNote, {
+    findNotes: async () => candidateIds,
+    notesInfo: async (noteIds) => {
+      notesInfoCalls += 1;
+      return noteIds.map((noteId) => ({
+        noteId,
+        fields: {
+          Expression: { value: noteId === 200 ? '貴様' : `別単語-${noteId}` },
+        },
+      }));
+    },
+    getDeck: () => 'Japanese::Mining',
+    resolveFieldName: (noteInfo, preferredName) => createFieldResolver(noteInfo, preferredName),
+    logWarn: () => {},
+  });
+
+  assert.equal(duplicateId, 200);
+  assert.equal(notesInfoCalls, 1);
+});
diff --git a/src/anki-integration/duplicate.ts b/src/anki-integration/duplicate.ts
index 09938918..882e500e 100644
--- a/src/anki-integration/duplicate.ts
+++ b/src/anki-integration/duplicate.ts
@@ -24,7 +24,13 @@ export async function findDuplicateNote(
   noteInfo: NoteInfo,
   deps: DuplicateDetectionDeps,
 ): Promise<number | null> {
-  const duplicateNoteIds = await findDuplicateNoteIds(expression, excludeNoteId, noteInfo, deps);
+  const duplicateNoteIds = await findDuplicateNoteIds(
+    expression,
+    excludeNoteId,
+    noteInfo,
+    deps,
+    1,
+  );
   return duplicateNoteIds[0] ?? null;
 }
 
@@ -33,6 +39,7 @@ export async function findDuplicateNoteIds(
   excludeNoteId: number,
   noteInfo: NoteInfo,
   deps: DuplicateDetectionDeps,
+  maxMatches?: number,
 ): Promise<number[]> {
   const configuredWordFieldCandidates = deps.getWordFieldCandidates?.() ?? ['Expression', 'Word'];
   const sourceCandidates = getDuplicateSourceCandidates(
@@ -99,6 +106,7 @@ export async function findDuplicateNoteIds(
       sourceCandidates.map((candidate) => candidate.value),
       configuredWordFieldCandidates,
       deps,
+      maxMatches,
     );
   } catch (error) {
     deps.logWarn('Duplicate search failed:', error);
@@ -112,6 +120,7 @@ function findExactDuplicateNoteIds(
   sourceValues: string[],
   candidateFieldNames: string[],
   deps: DuplicateDetectionDeps,
+  maxMatches?: number,
 ): Promise<number[]> {
   const candidates = Array.from(candidateNoteIds).filter((id) => id !== excludeNoteId);
   deps.logDebug?.(`[duplicate] candidateIds=${candidates.length} exclude=${excludeNoteId}`);
@@ -145,6 +154,9 @@ function findExactDuplicateNoteIds(
             );
             deps.logInfo?.(`[duplicate] matched noteId=${noteInfo.noteId} field=${resolvedField}`);
             matches.push(noteInfo.noteId);
+            if (maxMatches !== undefined && matches.length >= maxMatches) {
+              return matches;
+            }
             break;
           }
         }
diff --git a/src/core/services/tokenizer/yomitan-parser-runtime.test.ts b/src/core/services/tokenizer/yomitan-parser-runtime.test.ts
index 9e5cc01b..152cff28 100644
--- a/src/core/services/tokenizer/yomitan-parser-runtime.test.ts
+++ b/src/core/services/tokenizer/yomitan-parser-runtime.test.ts
@@ -1390,3 +1390,32 @@ test('addYomitanNoteViaSearch returns note and duplicate ids from the bridge pay
     duplicateNoteIds: [18, 7, 18],
   });
 });
+
+test('addYomitanNoteViaSearch rejects invalid numeric note ids from the bridge shortcut', async () => {
+  const deps = createDeps(async () => NaN);
+
+  const result = await addYomitanNoteViaSearch('食べる', deps, {
+    error: () => undefined,
+  });
+
+  assert.deepEqual(result, {
+    noteId: null,
+    duplicateNoteIds: [],
+  });
+});
+
+test('addYomitanNoteViaSearch sanitizes invalid payload note ids while keeping valid duplicate ids', async () => {
+  const deps = createDeps(async (_script) => ({
+    noteId: -1,
+    duplicateNoteIds: [18, 0, 7.5, 7],
+  }));
+
+  const result = await addYomitanNoteViaSearch('食べる', deps, {
+    error: () => undefined,
+  });
+
+  assert.deepEqual(result, {
+    noteId: null,
+    duplicateNoteIds: [18, 7],
+  });
+});
diff --git a/src/core/services/tokenizer/yomitan-parser-runtime.ts b/src/core/services/tokenizer/yomitan-parser-runtime.ts
index fadc983b..ffac7cc9 100644
--- a/src/core/services/tokenizer/yomitan-parser-runtime.ts
+++ b/src/core/services/tokenizer/yomitan-parser-runtime.ts
@@ -2010,7 +2010,10 @@ export async function addYomitanNoteViaSearch(
   try {
     const result = await parserWindow.webContents.executeJavaScript(script, true);
     if (typeof result === 'number') {
-      return { noteId: result, duplicateNoteIds: [] };
+      return {
+        noteId: Number.isInteger(result) && result > 0 ? result : null,
+        duplicateNoteIds: [],
+      };
     }
     if (result && typeof result === 'object' && !Array.isArray(result)) {
       const envelope = result as {
@@ -2018,7 +2021,12 @@ export async function addYomitanNoteViaSearch(
         duplicateNoteIds?: unknown;
       };
       return {
-        noteId: typeof envelope.noteId === 'number' ? envelope.noteId : null,
+        noteId:
+          typeof envelope.noteId === 'number' &&
+          Number.isInteger(envelope.noteId) &&
+          envelope.noteId > 0
+            ? envelope.noteId
+            : null,
         duplicateNoteIds: Array.isArray(envelope.duplicateNoteIds)
           ? envelope.duplicateNoteIds.filter(
               (entry): entry is number => typeof entry === 'number' && Number.isInteger(entry) && entry > 0,
diff --git a/src/renderer/handlers/keyboard.test.ts b/src/renderer/handlers/keyboard.test.ts
index 47f291b3..51496ccb 100644
--- a/src/renderer/handlers/keyboard.test.ts
+++ b/src/renderer/handlers/keyboard.test.ts
@@ -549,6 +549,31 @@ test('paused configured subtitle-jump keybinding re-applies pause after backward
   }
 });
 
+test('configured subtitle-jump keybinding preserves pause when pause state is unknown', async () => {
+  const { handlers, testGlobals } = createKeyboardHandlerHarness();
+
+  try {
+    await handlers.setupMpvInputForwarding();
+    handlers.updateKeybindings([
+      {
+        key: 'Shift+KeyH',
+        command: ['sub-seek', -1],
+      },
+    ] as never);
+    testGlobals.setPlaybackPausedResponse(null);
+
+    testGlobals.dispatchKeydown({ key: 'H', code: 'KeyH', shiftKey: true });
+    await wait(0);
+
+    assert.deepEqual(testGlobals.mpvCommands.slice(-2), [
+      ['sub-seek', -1],
+      ['set_property', 'pause', 'yes'],
+    ]);
+  } finally {
+    testGlobals.restore();
+  }
+});
+
 test('visible-layer y-t dispatches mpv plugin toggle while overlay owns focus', async () => {
   const { handlers, testGlobals } = createKeyboardHandlerHarness();
 
diff --git a/src/renderer/handlers/keyboard.ts b/src/renderer/handlers/keyboard.ts
index efca7f49..8bb1e22a 100644
--- a/src/renderer/handlers/keyboard.ts
+++ b/src/renderer/handlers/keyboard.ts
@@ -376,7 +376,7 @@ export function createKeyboardHandlers(
       .getPlaybackPaused()
       .then((paused) => {
         window.electronAPI.sendMpvCommand(command);
-        if (paused === true) {
+        if (paused !== false) {
           window.electronAPI.sendMpvCommand(['set_property', 'pause', 'yes']);
         }
       })