src/snek/static/chat-input.js

@@ -279,7 +279,8 @@ levenshteinDistance(a, b) {
       app.rpc &&
       typeof app.rpc.updateMessageText === "function"
     ) {
-      app.rpc.updateMessageText(this.messageUid, this.replaceMentionsWithAuthors(this.value));
+        this.value = this.replaceMentionsWithAuthors(this.value);
+      app.rpc.updateMessageText(this.messageUid, this.value);
     }
   }