diff --git a/src/@/components/SavedLinkCard.tsx b/src/@/components/SavedLinkCard.tsx
index a8c984e..d4e1411 100644
--- a/src/@/components/SavedLinkCard.tsx
+++ b/src/@/components/SavedLinkCard.tsx
@@ -72,6 +72,7 @@ function useSavedLinkPolling({
     useEffect(() => {
         let isMounted = true;
         let pollInterval: NodeJS.Timeout | null = null;
+        let timeoutId: NodeJS.Timeout | null = null;
         const hasSharedData = sharedImgSrc?.startsWith('data:');
 
         const fetchData = async () => {
@@ -91,7 +92,7 @@ function useSavedLinkPolling({
                         }
                     } catch { }
                 }, 2000);
-                setTimeout(() => { if (pollInterval) clearInterval(pollInterval); if (isMounted && !link.preview && !imgSrc) setIsLoading(false); }, 30000);
+                timeoutId = setTimeout(() => { if (pollInterval) clearInterval(pollInterval); if (isMounted && !link.preview && !imgSrc) setIsLoading(false); }, 30000);
                 return;
             }
 
@@ -110,7 +111,7 @@ function useSavedLinkPolling({
             }
         };
         fetchData();
-        return () => { isMounted = false; if (pollInterval) clearInterval(pollInterval); };
+        return () => { isMounted = false; if (pollInterval) clearInterval(pollInterval); if (timeoutId) clearTimeout(timeoutId); };
     }, [link.preview, link.url, link.id, baseUrl, sharedImgSrc, onImgSrcChange]);
 
     return { imgSrc, isLoading, isPollingTags, setIsPollingTags };
diff --git a/src/@/hooks/useThumbnail.ts b/src/@/hooks/useThumbnail.ts
index 7f4b26c..ea4668b 100644
--- a/src/@/hooks/useThumbnail.ts
+++ b/src/@/hooks/useThumbnail.ts
@@ -135,16 +135,21 @@ export function useThumbnail({
     useEffect(() => {
         if (!isLoading || imgSrc || !linkId || !baseUrl) return;
 
+        let cancelled = false;
+
         const pollInterval = setInterval(async () => {
             const apiImage = await fetchFromApi();
-            if (apiImage) {
+            if (!cancelled && apiImage) {
                 setImgSrc(apiImage);
                 setIsLoading(false);
                 clearInterval(pollInterval);
             }
         }, 3000);
 
-        return () => clearInterval(pollInterval);
+        return () => {
+            cancelled = true;
+            clearInterval(pollInterval);
+        };
     }, [isLoading, imgSrc, linkId, baseUrl, fetchFromApi]);
 
     return {
diff --git a/src/pages/ContentScript/SmartCapture/SmartCaptureMode.ts b/src/pages/ContentScript/SmartCapture/SmartCaptureMode.ts
index b9d6fed..4c4b799 100644
--- a/src/pages/ContentScript/SmartCapture/SmartCaptureMode.ts
+++ b/src/pages/ContentScript/SmartCapture/SmartCaptureMode.ts
@@ -33,6 +33,8 @@ export class SmartCaptureMode {
     private shortcutConfig: ShortcutConfig = DEFAULT_PREFERENCES.smartCaptureShortcut;
     private enableSmartCapture = DEFAULT_PREFERENCES.enableSmartCapture;
 
+    private storageChangeListener: (changes: { [key: string]: chrome.storage.StorageChange }, area: string) => void;
+
     private boundHandlers: {
         mousemove: (e: MouseEvent) => void;
         mousedown: (e: MouseEvent) => void;
@@ -74,11 +76,12 @@ export class SmartCaptureMode {
         document.addEventListener('keyup', this.globalKeyupHandler);
         const hostname = getHostname(window.location.href);
         getEffectivePreferences(hostname).then(prefs => { if (prefs) this.updateSettings(prefs); });
-        chrome.storage.onChanged.addListener((changes, area) => {
+        this.storageChangeListener = (changes, area) => {
             if (area === 'local' && (changes.grabshark_preferences || changes.grabshark_site_overrides)) {
                 getEffectivePreferences(getHostname(window.location.href)).then(prefs => this.updateSettings(prefs));
             }
-        });
+        };
+        chrome.storage.onChanged.addListener(this.storageChangeListener);
     }
     public updateSettings(prefs: ExtensionPreferences) {
         if (prefs.smartCaptureShortcut) this.shortcutConfig = prefs.smartCaptureShortcut;
@@ -293,5 +296,7 @@ export class SmartCaptureMode {
         try { this.deactivate(); } catch { }
         try { this.actionBar?.destroy(); } catch { }
         try { document.removeEventListener('keydown', this.globalKeydownHandler); document.removeEventListener('keyup', this.globalKeyupHandler); } catch { }
+        try { chrome.storage.onChanged.removeListener(this.storageChangeListener); } catch { }
+        if (this.animationFrameId) { cancelAnimationFrame(this.animationFrameId); this.animationFrameId = null; }
     }
 }
diff --git a/src/pages/ContentScript/highlightObserver.ts b/src/pages/ContentScript/highlightObserver.ts
index 0185090..9478dba 100644
--- a/src/pages/ContentScript/highlightObserver.ts
+++ b/src/pages/ContentScript/highlightObserver.ts
@@ -42,6 +42,11 @@ class HighlightObserver {
     };
 
     start(highlights: Highlight[], initialResults: Map<number, boolean>): void {
+        // If already observing, ensure we stop previous timers/observers before restarting or merging
+        if (this.isObserving) {
+            this.stop();
+        }
+
         highlights.forEach(h => this.state.allHighlights.set(h.id, h));
         this.state.lastDocHeight = document.body.scrollHeight;
 
diff --git a/yarn.lock b/yarn.lock
index 71c8eb1..e8d0f03 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -175,10 +175,10 @@
     "@babel/helper-string-parser" "^7.27.1"
     "@babel/helper-validator-identifier" "^7.28.5"
 
-"@esbuild/darwin-arm64@0.18.20":
+"@esbuild/linux-x64@0.18.20":
   version "0.18.20"
-  resolved "https://registry.npmjs.org/@esbuild/darwin-arm64/-/darwin-arm64-0.18.20.tgz"
-  integrity sha512-bxRHW5kHU38zS2lPTPOyuyTm+S+eobPUnTNkdJEfAddYgEcll4xkT8DB9d2008DtTbl7uJag2HuE5NZAZgnNEA==
+  resolved "https://registry.npmjs.org/@esbuild/linux-x64/-/linux-x64-0.18.20.tgz"
+  integrity sha512-UYqiqemphJcNsFEskc73jQ7B9jgwjWrSayxawS6UVFZGWrAAtkzjxSqnoclCXxWtfwLdzU+vTpcNYhpn43uP1w==
 
 "@eslint-community/eslint-utils@^4.2.0", "@eslint-community/eslint-utils@^4.4.0":
   version "4.4.0"
@@ -1818,11 +1818,6 @@ fs.realpath@^1.0.0:
   resolved "https://registry.npmjs.org/fs.realpath/-/fs.realpath-1.0.0.tgz"
   integrity sha512-OO0pH2lK6a0hZnAdau5ItzHPI6pUlvI7jMVnxUQRtw4owF2wk8lOSabtGDCTP4Ggrg2MbGnWO9X8K1t4+fGMDw==
 
-fsevents@~2.3.2:
-  version "2.3.2"
-  resolved "https://registry.npmjs.org/fsevents/-/fsevents-2.3.2.tgz"
-  integrity sha512-xiqMQR4xAeHTuB9uWm+fFRcIOgKBMiOBP+eXiyT7jsgVCq1bkVygt00oASowB7EdtpOHaaPgKt812P9ab+DDKA==
-
 function-bind@^1.1.1, function-bind@^1.1.2:
   version "1.1.2"
   resolved "https://registry.npmjs.org/function-bind/-/function-bind-1.1.2.tgz"