diff --git a/manifests/prometheus-rules.yaml b/manifests/prometheus-rules.yaml
index f35510b53feb0df789fad8cead803cb5c4ce1ee0..2f0eaa756004dc7f18674c9b7f1062a7a08c594a 100644
--- a/manifests/prometheus-rules.yaml
+++ b/manifests/prometheus-rules.yaml
@@ -1054,7 +1054,7 @@ spec:
         message: The configuration of the instances of the Alertmanager cluster `{{$labels.service}}`
           are out of sync.
       expr: |
-        count_values("config_hash", alertmanager_config_hash{job="alertmanager-main",namespace="monitoring"}) BY (service) / ON(service) GROUP_LEFT() label_replace(prometheus_operator_spec_replicas{job="prometheus-operator",namespace="monitoring",controller="alertmanager"}, "service", "alertmanager-$1", "name", "(.*)") != 1
+        count_values("config_hash", alertmanager_config_hash{job="alertmanager-main",namespace="monitoring"}) BY (service) / ON(service) GROUP_LEFT() label_replace(max(prometheus_operator_spec_replicas{job="prometheus-operator",namespace="monitoring",controller="alertmanager"}) by (name, job, namespace, controller), "service", "alertmanager-$1", "name", "(.*)") != 1
       for: 5m
       labels:
         severity: critical