diff --git a/scripts/cluster/run-production-acceptance.sh b/scripts/cluster/run-production-acceptance.sh
index 63f6677..bd511ca 100755
--- a/scripts/cluster/run-production-acceptance.sh
+++ b/scripts/cluster/run-production-acceptance.sh
@@ -333,6 +333,7 @@ report_root=
 stable_profile=P24
 active_profile=P24
 single_node_stable_slots=4
+single_node_finish_status=
 failure_reason=
 failure_gate_id=
 failure_recorded=false
@@ -3758,6 +3759,17 @@ finish_single_node_diagnostic() {
   task_state=$(database_query "
 SELECT count(*)||':'||count(*) FILTER (WHERE status='succeeded')||':'||count(*) FILTER (WHERE status IN ('queued','running'))
 FROM gateway_tasks WHERE acceptance_run_id='$run_id'::uuid;")
+  local task_total task_succeeded task_active task_state_extra
+  IFS=':' read -r task_total task_succeeded task_active task_state_extra <<<"$task_state"
+  if [[ $diagnostic_status == completed ]] &&
+     { [[ -n $task_state_extra ]] ||
+       [[ ! $task_total =~ ^[0-9]+$ ]] ||
+       [[ ! $task_succeeded =~ ^[0-9]+$ ]] ||
+       [[ ! $task_active =~ ^[0-9]+$ ]] ||
+       (( task_total <= 0 || task_succeeded != task_total || task_active != 0 )); }; then
+    diagnostic_status=failed
+    reason="single-node task terminal gate failed: state=$task_state"
+  fi
   local results_json=$temporary_root/single-node-results.json
   local -a result_files=()
   shopt -s nullglob
@@ -3794,12 +3806,13 @@ FROM gateway_tasks WHERE acceptance_run_id='$run_id'::uuid;")
   chmod 0600 "$report_root/single-node-summary.json"
   local finish_body
   finish_body=$(jq -cn \
-    --arg reason "single-node diagnostic completed; real upstream and certification intentionally skipped" \
+    --arg reason "$reason" \
     --arg status "$diagnostic_status" \
     --argjson stableSlots "$single_node_stable_slots" \
     '{passed:false,failureReason:$reason,report:{diagnosticStatus:$status,site:"ningbo",realUpstreamRequests:0,certification:false,stableVideoSlots:$stableSlots}}')
   admin_request POST "/api/admin/system/acceptance/runs/$run_id/finish" "$finish_body" "$finish_response"
   failure_recorded=true
+  single_node_finish_status=$diagnostic_status
   cleanup_single_node_emulator
   cleanup_single_node_kubernetes_resources
 }
@@ -3816,16 +3829,21 @@ run_single_node_acceptance() {
   fi
   local slots requests
   for slots in "${single_node_video_slots[@]}"; do
-    apply_single_node_capacity "$slots" || break
+    if ! apply_single_node_capacity "$slots"; then
+      finish_single_node_diagnostic failed "video capacity did not converge at slots=$slots"
+      return 1
+    fi
     requests=$((slots * 6))
-    (( requests < 64 )) && requests=64
+    (( requests < 24 )) && requests=24
     if ! run_single_node_profile image-video video-capacity "$slots" "$requests"; then
-      break
+      finish_single_node_diagnostic failed "video capacity diagnostic failed at slots=$slots"
+      return 1
     fi
     single_node_stable_slots=$slots
   done
   apply_single_node_capacity "$single_node_stable_slots"
   finish_single_node_diagnostic completed 'single-node emulator-only capacity ladder completed'
+  [[ $single_node_finish_status == completed ]] || return 1
   echo "single_node_acceptance=PASS_DIAGNOSTIC run_id=$run_id stable_video_slots=$single_node_stable_slots traffic_mode=validation certification=false report=$report_root/single-node-summary.json"
 }