diff --git a/app/models/formsemestre.py b/app/models/formsemestre.py
index 20a1cf359e..e29ffbfc31 100644
--- a/app/models/formsemestre.py
+++ b/app/models/formsemestre.py
@@ -195,6 +195,7 @@ class FormSemestre(db.Model):
         """
         d = dict(self.__dict__)
         d.pop("_sa_instance_state", None)
+        d.pop("groups_auto_assignment_data", None)
         # ScoDoc7 output_formators: (backward compat)
         d["formsemestre_id"] = self.id
         d["titre_num"] = self.titre_num()
@@ -226,6 +227,7 @@ class FormSemestre(db.Model):
         """
         d = dict(self.__dict__)
         d.pop("_sa_instance_state", None)
+        d.pop("groups_auto_assignment_data", None)
         d["annee_scolaire"] = self.annee_scolaire()
         if self.date_debut:
             d["date_debut"] = self.date_debut.strftime("%d/%m/%Y")