diff --git a/control/grpc.py b/control/grpc.py
index 899b3dae..1c14e4f7 100644
--- a/control/grpc.py
+++ b/control/grpc.py
@@ -476,7 +476,7 @@ def set_ana_state_safe(self, ana_info: pb2.ana_info, context=None):
         # Iterate over nqn_ana_states in ana_info
         for nas in ana_info.states:
             nqn = nas.nqn
-            prefix = f"{self.gateway_state.local.LISTENER_PREFIX}_{nqn}_{self.gateway_name}_"
+            prefix = f"{self.gateway_state.local.LISTENER_PREFIX}{nqn}_{self.gateway_name}_"
             listener_keys = [key for key in state.keys() if key.startswith(prefix)]
             self.logger.info(f"Iterate over {nqn=} {prefix=} {listener_keys=}")