diff --git a/hbd/server/threshold.py b/hbd/server/threshold.py
index ec50f03..9d88d83 100644
--- a/hbd/server/threshold.py
+++ b/hbd/server/threshold.py
@@ -1554,6 +1554,10 @@ class ThresholdChecker:
             configured = self.get_thresholds_for_host(hostname)
             stale = []
             for mp in host.alert_states:
+                # connectivity.* and rtt are managed by the connection state
+                # machine, not by threshold config — never purge them.
+                if mp == "rtt" or mp.startswith("connectivity."):
+                    continue
                 if self._find_threshold(configured, mp)[0] is not None:
                     continue
                 # Also match wildcard pool/partition thresholds (e.g. "zfs_monitor.*.status"