diff --git a/airflow/www/views.py b/airflow/www/views.py
index 8311050bfff56..5559ea45d874a 100644
--- a/airflow/www/views.py
+++ b/airflow/www/views.py
@@ -4408,7 +4408,10 @@ def prefill_form(self, form, pk):
             if is_sensitive and field_name in extra_dictionary:
                 extra_dictionary[field_name] = SENSITIVE_FIELD_PLACEHOLDER
         # form.data is a property that builds the dictionary from fields so we have to modify the fields
-        form.extra.data = json.dumps(extra_dictionary)
+        if extra_dictionary:
+            form.extra.data = json.dumps(extra_dictionary)
+        else:
+            form.extra.data = None
 
 
 class PluginView(AirflowBaseView):