diff --git a/jikimo_purchase_request_tier_validation/models/models.py b/jikimo_purchase_request_tier_validation/models/models.py
index 0070a4c7..3a8cb027 100644
--- a/jikimo_purchase_request_tier_validation/models/models.py
+++ b/jikimo_purchase_request_tier_validation/models/models.py
@@ -22,3 +22,9 @@ class PurchaseRequest(models.Model):
             self.state = 'approved'
 
         return res
+    
+    @api.model
+    def _get_under_validation_exceptions(self):
+        res = super(PurchaseRequest, self)._get_under_validation_exceptions()
+        res.append("state")
+        return res