Fix stale read on CreateDatasetElement

Closes #1754 (closed)

arkindex/training/serializers.py

@@ -717,7 +717,7 @@ class DatasetElementSerializer(serializers.ModelSerializer):
         super().__init__(*args, **kwargs)
         if dataset := self.context.get("dataset"):
             self.fields["element_id"].queryset = Element.objects.filter(corpus=dataset.corpus)
-            self.fields["set"].queryset = dataset.sets.all()
+            self.fields["set"].queryset = dataset.sets.using("default")
 
     def validate_element_id(self, element):
         dataset = self.context.get("dataset")