diff --git a/arkindex/ponos/api.py b/arkindex/ponos/api.py
index 302c60ce29aada004c99d7276588e2fcc82b00fc..368a44055b337a81a81b907d26b48c61e3df505d 100644
--- a/arkindex/ponos/api.py
+++ b/arkindex/ponos/api.py
@@ -235,7 +235,6 @@ class TaskRestart(ProcessACLMixin, CreateAPIView):
         parents = list(copy.parents.all())
 
         # Rename the original task
-        basename, *_ = copy.slug.rsplit("_old", 1)
         if copy.original_task_id:
             basename, *_ = copy.slug.rsplit("_old", 1)
         else:
diff --git a/arkindex/ponos/models.py b/arkindex/ponos/models.py
index d2c6ad7d76ae334d6dc883a61043e667ff90e7e8..76a91f8a152761d566d025ff9f2558f3db98fd6f 100644
--- a/arkindex/ponos/models.py
+++ b/arkindex/ponos/models.py
@@ -332,7 +332,6 @@ class Task(models.Model):
         null=True,
         blank=True,
     )
-
     original_task = models.ForeignKey(
         "self",
         on_delete=models.SET_NULL,
diff --git a/arkindex/ponos/tests/test_api.py b/arkindex/ponos/tests/test_api.py
index 0e21aa2a6293aa0c5f29e3e62c374c40ba86e385..7e9f2db698de79b7839e9ad8ded8762a6baf0b7c 100644
--- a/arkindex/ponos/tests/test_api.py
+++ b/arkindex/ponos/tests/test_api.py
@@ -635,6 +635,7 @@ class TestAPI(FixtureAPITestCase):
             mock_now.return_value = datetime.now(timezone.utc) + timedelta(minutes=1)
             old_task_2 = self.process.tasks.create(run=self.task1.run, depth=1, slug=f"{task_2_slug}_old1")
             old_task_2.state = State.Error.value
+            old_task_2.original_task_id = self.task1.id
             old_task_2.save()
         old_task_2.parents.add(self.task1)
         self.task1.state = State.Completed.value