diff --git a/infra/lib/constructs/app-service.ts b/infra/lib/constructs/app-service.ts
index fd724dbe..48607575 100644
--- a/infra/lib/constructs/app-service.ts
+++ b/infra/lib/constructs/app-service.ts
@@ -8,7 +8,7 @@ import * as logs from "aws-cdk-lib/aws-logs";
 import * as route53 from "aws-cdk-lib/aws-route53";
 import * as iam from "aws-cdk-lib/aws-iam";
 import * as ssm from "aws-cdk-lib/aws-ssm";
-import { Construct } from "constructs";
+import { Construct, IConstruct } from "constructs";
 import { EnvName, prefix } from "../config";
 import { bakedOpenSweArm64 } from "./ami-cache";
 
@@ -230,6 +230,27 @@ export class AppService extends Construct {
       ],
     });
 
+    // `requireImdsv2: true` makes CDK auto-create a launch template, and it names
+    // that LT from the construct id ("Instance" -> "InstanceLaunchTemplate") with NO
+    // env qualifier — so OpenSweDevStack and OpenSweProdStack both want the identical
+    // LT name and the second env to deploy fails with
+    // InvalidLaunchTemplateName.AlreadyExistsException (prod rollback, 2026-06-29).
+    // Force a per-env LT name. Done via an aspect because the LT is created at synth
+    // time by the requireImdsv2 handling, not in this constructor.
+    cdk.Aspects.of(this.instance).add({
+      visit(node: IConstruct) {
+        if (node instanceof ec2.CfnLaunchTemplate) {
+          node.launchTemplateName = `${p}-lt`;
+        }
+        // The instance references the LT BY NAME, so the reference must be renamed in
+        // lockstep (preserve the GetAtt version) or CFN can't find the template.
+        if (node instanceof ec2.CfnInstance && node.launchTemplate) {
+          const spec = node.launchTemplate as ec2.CfnInstance.LaunchTemplateSpecificationProperty;
+          node.launchTemplate = { ...spec, launchTemplateName: `${p}-lt` };
+        }
+      },
+    });
+
     // SSM deploy document (open-swe-<env>-deploy): runs the baked
     // /opt/open-swe/bin/deploy.sh to pull the latest release + restart. CI fires it
     // (tag-scoped to project=open-swe,env=<env>) after uploading a release, so the