diff --git a/src/upgrades/1.17.0/topic_thumb_count.js b/src/upgrades/1.17.0/topic_thumb_count.js
index a5239101d0..7e39b195ea 100644
--- a/src/upgrades/1.17.0/topic_thumb_count.js
+++ b/src/upgrades/1.17.0/topic_thumb_count.js
@@ -13,7 +13,7 @@ module.exports = {
 		await batch.processSortedSet('topics:tid', async (tids) => {
 			const keys = tids.map(tid => `topic:${tid}:thumbs`);
 			const counts = await db.sortedSetsCard(keys);
-			const tidToCount = _.zip(tids, counts);
+			const tidToCount = _.zipObject(tids, counts);
 			const tidsWithThumbs = tids.filter((t, i) => counts[i] > 0);
 			await db.setObjectBulk(
 				tidsWithThumbs.map(tid => `topic:${tid}`),