diff --git a/managers/mongodb_manager.py b/managers/mongodb_manager.py
index 3facc52..8faf040 100644
--- a/managers/mongodb_manager.py
+++ b/managers/mongodb_manager.py
@@ -125,7 +125,46 @@ class MongoDBArticleCache:
                 }
                 
                 # Preparar user_info basándose en lo que existe realmente en MongoDB
-                if existing is None:
+                if existing:
+                    existing_user_info = existing.get('user_info', [])
+
+                    # Buscar si ya existe user_info para este usuario
+                    user_info_index = None
+                    for i, ui in enumerate(existing_user_info):
+                        if ui.get('username') == username:
+                            user_info_index = i
+                            break
+
+                    if user_info_index is not None:
+                        # Actualizar user_info existente pero mantener notified_at original
+                        existing_user_info_entry = existing_user_info[user_info_index]
+                        existing_user_info[user_info_index] = {
+                            'username': existing_user_info_entry.get('username'),
+                            'worker_name': worker_name or existing_user_info_entry.get('worker_name'),
+                            'notified': True,
+                            'notified_at': existing_user_info_entry.get('notified_at'),
+                            'is_favorite': existing_user_info_entry.get('is_favorite', False),
+                        }
+                    else:
+                        existing_user_info.append({
+                            'username': username,
+                            'worker_name': worker_name,
+                            'notified': True,
+                            'notified_at': now,
+                            'is_favorite': False,
+                        })
+
+                    # Solo hacer update si el precio cambió
+                    if existing.get('price') != article.get_price():
+                        update_data = dict(base_fields)
+                        update_data['user_info'] = existing_user_info
+                        operations.append(
+                            UpdateOne(
+                                {'platform': platform, 'id': article_id},
+                                {'$set': update_data}
+                            )
+                        )
+                else:
                     # Artículo nuevo
                     new_article_data = dict(base_fields)
                     new_article_data['user_info'] = [{