diff --git a/internal/fleetobserve/metrics.go b/internal/fleetobserve/metrics.go
index 2376a1f..59c979f 100644
--- a/internal/fleetobserve/metrics.go
+++ b/internal/fleetobserve/metrics.go
@@ -169,15 +169,14 @@ func RenderPrometheus(snapshot Snapshot, now time.Time, maxStaleness time.Durati
 	labeledGaugeHeader(&output, "gha_fleet_queue_oldest_queued_wait_seconds_by_scale_set", "Longest wait since GitHub queued a still-queued intent, per configured scale set.")
 	for _, scaleSet := range scaleSets {
 		metric(&output, "gha_fleet_queue_oldest_queued_wait_seconds_by_scale_set", map[string]string{"scale_set": scaleSet}, float64(snapshot.Queue.OldestQueuedWaitSecondsByScaleSet[scaleSet]))
-
-		gauge(&output, "gha_fleet_queue_started_wait_samples", "Jobs whose runner started within the completed-wait window.", float64(snapshot.Queue.StartedWaitSamples))
-		gauge(&output, "gha_fleet_queue_started_wait_median_seconds", "Median wait, first queued to runner running, over jobs that started in the window.", float64(snapshot.Queue.StartedWaitMedianSeconds))
-		gauge(&output, "gha_fleet_queue_started_wait_p90_seconds", "Ninetieth-percentile wait, first queued to runner running, over jobs that started in the window.", float64(snapshot.Queue.StartedWaitP90Seconds))
-		gauge(&output, "gha_fleet_queue_started_wait_max_seconds", "Longest wait, first queued to runner running, over jobs that started in the window.", float64(snapshot.Queue.StartedWaitMaxSeconds))
-		labeledGaugeHeader(&output, "gha_fleet_queue_started_wait_p90_seconds_by_scale_set", "Ninetieth-percentile completed wait per scale set.")
-		for _, scaleSet := range scaleSets {
-			metric(&output, "gha_fleet_queue_started_wait_p90_seconds_by_scale_set", map[string]string{"scale_set": scaleSet}, float64(snapshot.Queue.StartedWaitP90ByScaleSet[scaleSet]))
-		}
+	}
+	gauge(&output, "gha_fleet_queue_started_wait_samples", "Jobs whose runner started within the completed-wait window.", float64(snapshot.Queue.StartedWaitSamples))
+	gauge(&output, "gha_fleet_queue_started_wait_median_seconds", "Median wait, first queued to runner running, over jobs that started in the window.", float64(snapshot.Queue.StartedWaitMedianSeconds))
+	gauge(&output, "gha_fleet_queue_started_wait_p90_seconds", "Ninetieth-percentile wait, first queued to runner running, over jobs that started in the window.", float64(snapshot.Queue.StartedWaitP90Seconds))
+	gauge(&output, "gha_fleet_queue_started_wait_max_seconds", "Longest wait, first queued to runner running, over jobs that started in the window.", float64(snapshot.Queue.StartedWaitMaxSeconds))
+	labeledGaugeHeader(&output, "gha_fleet_queue_started_wait_p90_seconds_by_scale_set", "Ninetieth-percentile completed wait per scale set.")
+	for _, scaleSet := range scaleSets {
+		metric(&output, "gha_fleet_queue_started_wait_p90_seconds_by_scale_set", map[string]string{"scale_set": scaleSet}, float64(snapshot.Queue.StartedWaitP90ByScaleSet[scaleSet]))
 	}
 	gauge(&output, "gha_fleet_incus_visible_instances", "Instances visible in the restricted Incus project.", float64(snapshot.Incus.VisibleInstances))
 	gauge(&output, "gha_fleet_incus_visible_maintenance_instances", "Visible exact image builder or smoke instances; observable maintenance capacity, never GitHub job runners.", float64(snapshot.Incus.VisibleMaintenanceInstances))
diff --git a/internal/fleetobserve/metrics_test.go b/internal/fleetobserve/metrics_test.go
index f98bc6d..2aaf09b 100644
--- a/internal/fleetobserve/metrics_test.go
+++ b/internal/fleetobserve/metrics_test.go
@@ -88,6 +88,24 @@ func TestRenderPrometheusIsDeterministicAndBounded(t *testing.T) {
 	}
 }
 
+func TestRenderPrometheusEmitsEverySeriesOnce(t *testing.T) {
+	metrics := RenderPrometheus(healthyCollector(t).Collect(t.Context()), observationTime, 45*time.Second)
+	seen := map[string]bool{}
+	for line := range strings.Lines(metrics) {
+		if strings.HasPrefix(line, "#") || strings.TrimSpace(line) == "" {
+			continue
+		}
+		series, _, ok := strings.Cut(strings.TrimSpace(line), " ")
+		if !ok {
+			t.Fatalf("metric line has no value: %q", line)
+		}
+		if seen[series] {
+			t.Fatalf("Prometheus series emitted more than once: %s", series)
+		}
+		seen[series] = true
+	}
+}
+
 func TestRenderPrometheusExposesBoundedDiagnosticConvergence(t *testing.T) {
 	collector := healthyCollector(t)
 	collector.Diagnostics = func(time.Time) (workerdiagnostics.SpoolStats, error) {