diff --git a/swh/lister/core/lister_base.py b/swh/lister/core/lister_base.py
--- a/swh/lister/core/lister_base.py
+++ b/swh/lister/core/lister_base.py
@@ -480,7 +480,8 @@
             return '%s-%s' % (_type, _url)
 
         def _task_key(m):
-            return '%s-%s' % (m['type'], json.dumps(m['arguments']))
+            return '%s-%s' % (m['type'],
+                              json.dumps(m['arguments'], sort_keys=True))
 
         for m in models_list:
             ir = injected_repos[m['uid']]