diff --git a/frontend/src/stores.js b/frontend/src/stores.js
index 7cbbdd7..4523f0a 100644
--- a/frontend/src/stores.js
+++ b/frontend/src/stores.js
@@ -159,7 +159,7 @@ class MessageStore extends Store {
         if (userInfoStore.value && (message.author_id === userInfoStore.value.id || userInfoStore.value.is_superuser)) {
             message._editable = true;
         }
-        if (previous && (message._createdAtDate.getTime() - previous._createdAtDate.getTime()) <= 100 * 1000) {
+        if (previous && (message._createdAtDate.getTime() - previous._createdAtDate.getTime()) <= 100 * 1000 && message.author_id === previous.author_id) {
             message._clumped = true;
         }
         if (previous && (previous._createdAtDateString !== message._createdAtDateString)) {