diff --git a/libervia/backend/plugins/plugin_xep_0060.py b/libervia/backend/plugins/plugin_xep_0060.py
index be92080f..9cbf4161 100644
--- a/libervia/backend/plugins/plugin_xep_0060.py
+++ b/libervia/backend/plugins/plugin_xep_0060.py
@@ -1989,7 +1989,7 @@ class SatPubSubClient(rsm.PubSubClient):
         @param event(unicode): one of C.PS_ITEMS, C.PS_RETRACT, C.PS_DELETE
         @return (iterator[callable]): callbacks for this node/event
         """
-        for registered_node, monitor_data in self.parent_plugin._node_cb.items():
+        for registered_node, monitor_data in list(self.parent_plugin._node_cb.items()):
             if monitor_data.strict_match:
                 if node != registered_node:
                     continue