diff --git a/js/webmentions.js b/js/webmentions.js
index 3f69f0f..145840e 100644
--- a/js/webmentions.js
+++ b/js/webmentions.js
@@ -57,8 +57,11 @@
 
     let mentionsToShow;
     if (hasBuildTimeSection) {
-      // Build-time section exists - only show NEW webmentions to avoid duplicates
+      // Build-time section exists - only show NEW webmentions to avoid duplicates.
+      // Conversations items (which have a 'platform' field) are never included
+      // in the build-time cache, so always show them regardless of timestamp.
       mentionsToShow = allChildren.filter((wm) => {
+        if (wm.platform) return true;
         const wmTime = new Date(wm['wm-received']).getTime();
         return wmTime > buildTime;
       });