diff --git a/lib/hooks/thread-time.js b/lib/hooks/thread-time.js
--- a/lib/hooks/thread-time.js
+++ b/lib/hooks/thread-time.js
@@ -81,9 +81,10 @@
         // (newest first) to chain together lastUpdatedTime. An older message's
         // lastUpdatedTime is only considered if all of the newer messages
         // return falsey.
+        const prevLastUpdatedTime = lastUpdatedTime;
         lastUpdatedTime = async () => {
-          if (lastUpdatedTime) {
-            const earlierChecks = await lastUpdatedTime();
+          if (prevLastUpdatedTime) {
+            const earlierChecks = await prevLastUpdatedTime();
             if (earlierChecks) {
               return earlierChecks;
             }