Ticket #8134: intermediaryfixtures.diff

django/core/serializers/base.py

@@ -168 +168 @@
         models.Model.save_base(self.object, raw=True)
         if self.m2m_data and save_m2m:
             for accessor_name, object_list in self.m2m_data.items():
-                setattr(self.object, accessor_name, object_list)
+                if not getattr(self.object, accessor_name).through:
+                    setattr(self.object, accessor_name, object_list)
 
         # prevent a second (possibly accidental) call to save() from saving
         # the m2m data twice.