diff --git a/cmd/compute-domain-controller/cdstatus.go b/cmd/compute-domain-controller/cdstatus.go
index 8d373769d..3c239ec13 100644
--- a/cmd/compute-domain-controller/cdstatus.go
+++ b/cmd/compute-domain-controller/cdstatus.go
@@ -351,6 +351,22 @@ func (m *ComputeDomainStatusManager) getNonStaleFabricNodes(existingNodes []*nva
 	return result
 }
 
+func validateCDStatusNodes(cd *nvapi.ComputeDomain) {
+	type cliqueIndexKey struct {
+		cliqueID string
+		index    int
+	}
+	seen := make(map[cliqueIndexKey]string)
+	for _, node := range cd.Status.Nodes {
+		key := cliqueIndexKey{cliqueID: node.CliqueID, index: node.Index}
+		if prevNodeName, exists := seen[key]; exists {
+			klog.Fatalf("ComputeDomain %s/%s status invariant violated: node index %d in clique %q is used by both node %q and node %q",
+				cd.Namespace, cd.Name, node.Index, node.CliqueID, prevNodeName, node.Name)
+		}
+		seen[key] = node.Name
+	}
+}
+
 // nodesEqual checks if two slices of ComputeDomainNode are equal.
 func (m *ComputeDomainStatusManager) nodesEqual(a, b []*nvapi.ComputeDomainNode) bool {
 	aMap := make(map[string]nvapi.ComputeDomainNode)
diff --git a/cmd/compute-domain-controller/computedomain.go b/cmd/compute-domain-controller/computedomain.go
index d338478bd..2b488d359 100644
--- a/cmd/compute-domain-controller/computedomain.go
+++ b/cmd/compute-domain-controller/computedomain.go
@@ -207,6 +207,9 @@ func (m *ComputeDomainManager) UpdateStatus(ctx context.Context, cd *nvapi.Compu
 	// Recalculate global status based on current state
 	cd.Status.Status = m.calculateGlobalStatus(cd)
 
+	// Validate status invariants: crash loudly if a node index is used more than once.
+	validateCDStatusNodes(cd)
+
 	updatedCD, err := m.config.clientsets.Nvidia.ResourceV1beta1().ComputeDomains(cd.Namespace).UpdateStatus(ctx, cd, metav1.UpdateOptions{})
 	if err != nil {
 		return nil, err