fix: Breaking cost center validation
diff --git a/erpnext/controllers/accounts_controller.py b/erpnext/controllers/accounts_controller.py
index c409850..996c4ed 100644
--- a/erpnext/controllers/accounts_controller.py
+++ b/erpnext/controllers/accounts_controller.py
@@ -368,6 +368,11 @@
 					if self.doctype in ["Purchase Invoice", "Sales Invoice"] and item.meta.get_field('is_fixed_asset'):
 						item.set('is_fixed_asset', ret.get('is_fixed_asset', 0))
 
+					# Double check for cost center
+					# Items add via promotional scheme may not have cost center set
+					if hasattr(item, 'cost_center') and not item.get('cost_center'):
+						item.set('cost_center', self.get('cost_center') or erpnext.get_default_cost_center(self.company))
+
 					if ret.get("pricing_rules"):
 						self.apply_pricing_rule_on_items(item, ret)
 						self.set_pricing_rule_details(item, ret)