# django__django-13964
# Loki Mode Multi-Agent Patch
# Attempts: 1

--- a/django/db/models/base.py
+++ b/django/db/models/base.py
@@ -933,7 +933,7 @@ class Model(AltersData, metaclass=ModelBase):
             # If the related field isn't cached, then an instance hasn't been
             # assigned and there's no need to worry about this check.
             if field.is_cached(self):
-                if getattr(self, field.attname) is None:
+                if getattr(self, field.attname) in field.empty_values:
                     obj = getattr(self, field.name)
                     if obj and obj.pk is not None:
                         setattr(self, field.attname, obj.pk)