diff --git a/js/utils/videoDeduper.js b/js/utils/videoDeduper.js
index 76575c42..bfbe8c05 100644
--- a/js/utils/videoDeduper.js
+++ b/js/utils/videoDeduper.js
@@ -8,6 +8,11 @@
 export function dedupeToNewestByRoot(videos) {
   const map = new Map();
 
+  const normalizeTimestamp = (value) => {
+    const numeric = Number(value);
+    return Number.isFinite(numeric) ? numeric : -Infinity;
+  };
+
   for (const vid of videos || []) {
     if (!vid) {
       continue;
@@ -18,7 +23,10 @@ export function dedupeToNewestByRoot(videos) {
     }
 
     const existing = map.get(rootId);
-    if (!existing || vid.created_at > existing.created_at) {
+    if (
+      !existing ||
+      normalizeTimestamp(vid.created_at) > normalizeTimestamp(existing.created_at)
+    ) {
       map.set(rootId, vid);
     }
   }
diff --git a/tests/utils/video-deduper.test.mjs b/tests/utils/video-deduper.test.mjs
new file mode 100644
index 00000000..5c149584
--- /dev/null
+++ b/tests/utils/video-deduper.test.mjs
@@ -0,0 +1,23 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+
+import { dedupeToNewestByRoot } from "../../js/utils/videoDeduper.js";
+
+test("dedupeToNewestByRoot replaces entries with missing timestamps", () => {
+  const original = { id: "abc", created_at: undefined };
+  const newer = { id: "abc", created_at: 123 };
+
+  const [result] = dedupeToNewestByRoot([original, newer]);
+
+  assert.equal(result, newer);
+});
+
+test("dedupeToNewestByRoot replaces entries with non-numeric timestamps", () => {
+  const rootId = "root-1";
+  const invalid = { id: "old", videoRootId: rootId, created_at: "not-a-number" };
+  const newer = { id: "new", videoRootId: rootId, created_at: "456" };
+
+  const [result] = dedupeToNewestByRoot([invalid, newer]);
+
+  assert.equal(result, newer);
+});