diff --git a/package.json b/package.json
index e86214f..ac8fdf6 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "openreader",
-  "version": "v2.1.1",
+  "version": "2.1.1",
   "private": true,
   "scripts": {
     "dev": "node scripts/openreader-entrypoint.mjs -- pnpm dev:raw",
diff --git a/src/app/api/tts/voices/route.ts b/src/app/api/tts/voices/route.ts
index 913e0e2..31f1155 100644
--- a/src/app/api/tts/voices/route.ts
+++ b/src/app/api/tts/voices/route.ts
@@ -22,6 +22,7 @@ export async function GET(req: NextRequest) {
     });
     return NextResponse.json({ voices });
   } catch (error) {
+    // This catch mainly guards auth/session access failures; voice resolution itself falls back internally.
     console.error('Error in voices endpoint:', error);
     const provider = req.headers.get('x-tts-provider') || 'openai';
     const model = req.headers.get('x-tts-model') || 'tts-1';
diff --git a/src/contexts/ConfigContext.tsx b/src/contexts/ConfigContext.tsx
index d0de9e9..5bcd124 100644
--- a/src/contexts/ConfigContext.tsx
+++ b/src/contexts/ConfigContext.tsx
@@ -257,7 +257,7 @@ export function ConfigProvider({ children }: { children: ReactNode }) {
     });
 
     return () => controller.abort();
-  }, [isDBReady, authEnabled, appConfig, buildSyncedPreferencePatch, isSessionPending, sessionKey]);
+  }, [isDBReady, authEnabled, appConfig, isSessionPending, sessionKey]);
 
   // Destructure for convenience and to match context shape
   const {
@@ -326,9 +326,13 @@ export function ConfigProvider({ children }: { children: ReactNode }) {
       }, key, value);
 
       await updateAppConfig(storagePatch);
-      if (key === 'voice' || key === 'ttsProvider' || key === 'ttsModel' || key === 'savedVoices') {
-        queueSyncedPreferencePatch(syncPatch);
-      } else if (syncedPreferenceKeys.has(String(key))) {
+      if (
+        key === 'voice' ||
+        key === 'ttsProvider' ||
+        key === 'ttsModel' ||
+        key === 'savedVoices' ||
+        syncedPreferenceKeys.has(String(key))
+      ) {
         queueSyncedPreferencePatch(syncPatch);
       }
     } catch (error) {
diff --git a/src/lib/client/audiobooks/adapters/epub.ts b/src/lib/client/audiobooks/adapters/epub.ts
index 6b69be0..ecd71cc 100644
--- a/src/lib/client/audiobooks/adapters/epub.ts
+++ b/src/lib/client/audiobooks/adapters/epub.ts
@@ -23,7 +23,8 @@ async function buildPreparedEpubChapters({
   for (const chapter of chapters) {
     if (!chapter.href) continue;
     const chapterBaseHref = chapter.href.split('#')[0];
-    const chapterTitle = chapter.label.trim();
+    const chapterTitle = typeof chapter.label === 'string' ? chapter.label.trim() : '';
+    if (!chapterTitle) continue;
 
     for (const section of sections) {
       const sectionBaseHref = section.href.split('#')[0];
@@ -41,12 +42,24 @@ async function buildPreparedEpubChapters({
 }
 
 export function createEpubAudiobookSourceAdapter(options: EpubAudiobookAdapterOptions): AudiobookSourceAdapter {
+  let preparedChaptersPromise: Promise<PreparedAudiobookChapter[]> | null = null;
+
+  const getPreparedChapters = () => {
+    if (!preparedChaptersPromise) {
+      preparedChaptersPromise = buildPreparedEpubChapters(options).catch((error) => {
+        preparedChaptersPromise = null;
+        throw error;
+      });
+    }
+    return preparedChaptersPromise;
+  };
+
   return {
     noContentMessage: 'No text content found in book',
     noAudioGeneratedMessage: 'No audio was generated from the book content',
-    prepareChapters: async () => buildPreparedEpubChapters(options),
+    prepareChapters: async () => getPreparedChapters(),
     prepareChapter: async (chapterIndex: number) => {
-      const chapters = await buildPreparedEpubChapters(options);
+      const chapters = await getPreparedChapters();
       const chapter = chapters[chapterIndex];
       if (!chapter) {
         throw new Error('Invalid chapter index');
diff --git a/src/lib/client/audiobooks/pipeline.ts b/src/lib/client/audiobooks/pipeline.ts
index 66dc2e4..295cef4 100644
--- a/src/lib/client/audiobooks/pipeline.ts
+++ b/src/lib/client/audiobooks/pipeline.ts
@@ -174,7 +174,11 @@ export async function runAudiobookGeneration({
       }
 
       if (!bookId) {
-        bookId = createdChapter.bookId!;
+        if (createdChapter.bookId) {
+          bookId = createdChapter.bookId;
+        } else {
+          throw new Error('Created chapter is missing bookId');
+        }
       }
 
       onChapterComplete?.(createdChapter);
diff --git a/src/lib/client/config/preferences.ts b/src/lib/client/config/preferences.ts
index 1a3e019..261a000 100644
--- a/src/lib/client/config/preferences.ts
+++ b/src/lib/client/config/preferences.ts
@@ -1,6 +1,36 @@
 import { APP_CONFIG_DEFAULTS, type AppConfigValues } from '@/types/config';
 import { SYNCED_PREFERENCE_KEYS, type SyncedPreferenceKey, type SyncedPreferencesPatch } from '@/types/user-state';
 
+function isObjectLike(value: unknown): value is Record<string, unknown> {
+  return typeof value === 'object' && value !== null;
+}
+
+function deepEqual(left: unknown, right: unknown): boolean {
+  if (left === right) return true;
+
+  if (Array.isArray(left) && Array.isArray(right)) {
+    if (left.length !== right.length) return false;
+    for (let i = 0; i < left.length; i += 1) {
+      if (!deepEqual(left[i], right[i])) return false;
+    }
+    return true;
+  }
+
+  if (isObjectLike(left) && isObjectLike(right)) {
+    const leftKeys = Object.keys(left);
+    const rightKeys = Object.keys(right);
+    if (leftKeys.length !== rightKeys.length) return false;
+
+    for (const key of leftKeys) {
+      if (!(key in right)) return false;
+      if (!deepEqual(left[key], right[key])) return false;
+    }
+    return true;
+  }
+
+  return false;
+}
+
 export function buildSyncedPreferencePatch(
   source: Partial<AppConfigValues>,
   options?: { nonDefaultOnly?: boolean },
@@ -16,7 +46,7 @@ export function buildSyncedPreferencePatch(
       const defaultValue = APP_CONFIG_DEFAULTS[key];
       const same =
         typeof value === 'object'
-          ? JSON.stringify(value) === JSON.stringify(defaultValue)
+          ? deepEqual(value, defaultValue)
           : value === defaultValue;
       if (same) continue;
     }
diff --git a/src/lib/shared/tts-provider-catalog.ts b/src/lib/shared/tts-provider-catalog.ts
index 243acf6..4713b34 100644
--- a/src/lib/shared/tts-provider-catalog.ts
+++ b/src/lib/shared/tts-provider-catalog.ts
@@ -167,14 +167,22 @@ export function resolveVoiceSource(provider: string, model: string): TtsVoiceSou
 }
 
 async function fetchDeepinfraVoices(apiKey: string): Promise<string[]> {
+  const controller = new AbortController();
+  const timeoutId = setTimeout(() => {
+    controller.abort();
+  }, 10_000);
+
   try {
     const response = await fetch('https://api.deepinfra.com/v1/voices', {
+      signal: controller.signal,
       headers: {
         'Content-Type': 'application/json',
         Authorization: `Bearer ${apiKey}`,
       },
     });
 
+    clearTimeout(timeoutId);
+
     if (!response.ok) {
       throw new Error('Failed to fetch Deepinfra voices');
     }
@@ -187,6 +195,10 @@ async function fetchDeepinfraVoices(apiKey: string): Promise<string[]> {
     }
     return [];
   } catch (error) {
+    clearTimeout(timeoutId);
+    if (error instanceof DOMException && error.name === 'AbortError') {
+      return [];
+    }
     console.error('Error fetching Deepinfra voices:', error);
     return [];
   }
@@ -194,7 +206,8 @@ async function fetchDeepinfraVoices(apiKey: string): Promise<string[]> {
 
 async function fetchCustomOpenAiVoices(baseUrl: string, apiKey: string): Promise<string[] | null> {
   try {
-    const response = await fetch(`${baseUrl}/audio/voices`, {
+    const normalizedBaseUrl = baseUrl.replace(/\/+$/, '');
+    const response = await fetch(`${normalizedBaseUrl}/audio/voices`, {
       headers: {
         Authorization: `Bearer ${apiKey}`,
         'Content-Type': 'application/json',
@@ -230,7 +243,7 @@ export async function resolveVoices({ provider, model, apiKey = '', baseUrl = ''
       return defaultVoices;
     }
     const apiVoices = await fetchCustomOpenAiVoices(baseUrl, apiKey);
-    if (apiVoices && apiVoices.length > 0) {
+    if (apiVoices !== null) {
       return apiVoices;
     }
   }
diff --git a/tests/helpers.ts b/tests/helpers.ts
index 65a5b19..21270a9 100644
--- a/tests/helpers.ts
+++ b/tests/helpers.ts
@@ -95,8 +95,6 @@ export async function uploadAndDisplay(page: Page, fileName: string) {
       break;
     } catch (error) {
       if (attempt === 2) throw error;
-      const message = String(error);
-      if (!message.includes('intercepts pointer events')) throw error;
       await page.waitForTimeout(200);
     }
   }
@@ -118,15 +116,18 @@ async function dismissSettingsModalIfVisible(page: Page): Promise<void> {
   const saveBtn = settingsDialog.getByRole('button', { name: 'Save' });
   const saveVisible = await saveBtn.isVisible().catch(() => false);
   if (saveVisible) {
-    await expect(saveBtn).toBeEnabled({ timeout: 10000 }).catch(() => { });
-    await saveBtn.click({ force: true }).catch(async () => {
-      await page.keyboard.press('Escape').catch(() => { });
-    });
+    const saveEnabled = await saveBtn.isEnabled();
+    if (saveEnabled) {
+      await saveBtn.focus();
+      await page.keyboard.press('Enter');
+    } else {
+      await page.keyboard.press('Escape');
+    }
   } else {
-    await page.keyboard.press('Escape').catch(() => { });
+    await page.keyboard.press('Escape');
   }
 
-  await settingsDialog.waitFor({ state: 'hidden', timeout: 15000 }).catch(() => { });
+  await settingsDialog.waitFor({ state: 'hidden', timeout: 15000 });
 }
 
 /**
diff --git a/tests/unit/tts-provider-catalog.spec.ts b/tests/unit/tts-provider-catalog.spec.ts
index dfd7ba7..120bd10 100644
--- a/tests/unit/tts-provider-catalog.spec.ts
+++ b/tests/unit/tts-provider-catalog.spec.ts
@@ -3,6 +3,7 @@ import { expect, test } from '@playwright/test';
 import {
   getDefaultVoices,
   providerSupportsCustomModel,
+  resolveVoices,
   resolveProviderModels,
   supportsTtsInstructions,
 } from '../../src/lib/shared/tts-provider-catalog';
@@ -48,6 +49,25 @@ test.describe('tts provider catalog', () => {
     expect(providerSupportsCustomModel('openai')).toBe(false);
     expect(providerSupportsCustomModel('deepinfra')).toBe(true);
   });
+
+  test('keeps explicit empty custom-openai voices response', async () => {
+    const originalFetch = globalThis.fetch;
+    globalThis.fetch = async () => ({
+      ok: true,
+      json: async () => ({ voices: [] }),
+    }) as Response;
+
+    try {
+      await expect(resolveVoices({
+        provider: 'custom-openai',
+        model: 'kokoro',
+        apiKey: 'token',
+        baseUrl: 'https://example.com',
+      })).resolves.toEqual([]);
+    } finally {
+      globalThis.fetch = originalFetch;
+    }
+  });
 });
 
 test.describe('config helpers', () => {