diff --git a/scripts/maintenance/computational-clusters/autoscaled_monitor/core.py b/scripts/maintenance/computational-clusters/autoscaled_monitor/core.py
index 9a076d11d7f8..4eff89026dd6 100755
--- a/scripts/maintenance/computational-clusters/autoscaled_monitor/core.py
+++ b/scripts/maintenance/computational-clusters/autoscaled_monitor/core.py
@@ -457,7 +457,11 @@ def _print_summary_as_json(
                     "user_id": cluster.primary.user_id,
                     "wallet_id": cluster.primary.wallet_id,
                     "disk_space": cluster.primary.disk_space.human_readable(),
-                    "last_heartbeat": cluster.primary.last_heartbeat.isoformat(),
+                    "last_heartbeat": (
+                        cluster.primary.last_heartbeat.isoformat()
+                        if cluster.primary.last_heartbeat
+                        else "n/a"
+                    ),
                 },
                 "workers": [
                     {
@@ -806,6 +810,7 @@ async def terminate_dynamic_instances(
         rich.print("no instances found")
         raise typer.Exit(1)
 
+    assert state.ec2_resource_autoscaling  # nosec
     _print_dynamic_instances(
         dynamic_autoscaled_instances,
         state.environment,