diff --git a/awx/api/serializers.py b/awx/api/serializers.py
index a5dee2dc27..42ef6f16f6 100644
--- a/awx/api/serializers.py
+++ b/awx/api/serializers.py
@@ -1640,6 +1640,7 @@ class InventorySourceSerializer(UnifiedJobTemplateSerializer, InventorySourceOpt
     def validate_source_project(self, value):
         if value.scm_type == '':
             raise serializers.ValidationError(_("Can not use manual project for SCM-based inventory."))
+        return value
 
     def validate_source(self, value):
         if value == '':