diff --git a/issue/models.py b/issue/models.py
index af270dfd..9457f133 100644
--- a/issue/models.py
+++ b/issue/models.py
@@ -55,8 +55,8 @@ def data(self):
             number=self.number,
             supplement=self.supplement,
             publication_year=self.publication_year,
-            created=created.isoformat(),
-            updated=updated.isoformat(),
+            created=self.created.isoformat(),
+            updated=self.updated.isoformat(),
         )
 
     @staticmethod
diff --git a/proc/models.py b/proc/models.py
index 45c6dce1..59d8acaf 100644
--- a/proc/models.py
+++ b/proc/models.py
@@ -6,7 +6,7 @@
 from tempfile import TemporaryDirectory
 
 from django.core.files.base import ContentFile
-from django.db import models
+from django.db import models, IntegrityError
 from django.db.models import Q
 from django.utils.translation import gettext_lazy as _
 from modelcluster.fields import ParentalKey