diff --git a/helm/argo-stack/overlays/ingress-authz-overlay/README.md b/helm/argo-stack/overlays/ingress-authz-overlay/README.md
index d07fe2c1..85f90f4d 100644
--- a/helm/argo-stack/overlays/ingress-authz-overlay/README.md
+++ b/helm/argo-stack/overlays/ingress-authz-overlay/README.md
@@ -64,6 +64,27 @@ See the [User Guide](docs/authz-ingress-user-guide.md) for architecture diagrams
 - NGINX Ingress Controller
 - cert-manager (for TLS) - **must be installed before deploying this overlay**
 
+### TLS Certificate Ownership
+
+When using cert-manager's ingress-shim, only **one** ingress resource can "own" a Certificate. 
+This overlay uses a `primary: true` flag on routes to designate which ingress should have the 
+`cert-manager.io/cluster-issuer` annotation.
+
+By default, the `workflows` route is set as primary. Other ingresses reference the same TLS 
+secret but without the cluster-issuer annotation, avoiding the "certificate resource is not 
+owned by this object" error.
+
+To change the primary route:
+
+```yaml
+ingressAuthzOverlay:
+  routes:
+    workflows:
+      primary: false  # Remove primary from workflows
+    applications:
+      primary: true   # Make applications the primary
+```
+
 ### Installing cert-manager
 
 If you see `no matches for kind "ClusterIssuer"`, cert-manager is not installed:
diff --git a/helm/argo-stack/overlays/ingress-authz-overlay/docs/authz-ingress-user-guide.md b/helm/argo-stack/overlays/ingress-authz-overlay/docs/authz-ingress-user-guide.md
index 4e57dbe7..e5e919ba 100644
--- a/helm/argo-stack/overlays/ingress-authz-overlay/docs/authz-ingress-user-guide.md
+++ b/helm/argo-stack/overlays/ingress-authz-overlay/docs/authz-ingress-user-guide.md
@@ -193,6 +193,41 @@ Common issues:
 - **ACME Registration Failed**: Check your email address is valid and you can reach Let's Encrypt's API
 - **Secret Not Found in Expected Namespace**: The secret is created in the cert-manager namespace, not your application namespace
 
+### TLS Certificate Ownership
+
+When using multiple ingress resources with the same TLS secret and cert-manager's ingress-shim, you may encounter an error:
+
+```
+certificate resource is not owned by this object. refusing to update non-owned certificate resource
+```
+
+This happens because **cert-manager only allows one Ingress to own a Certificate**. When multiple ingresses have the `cert-manager.io/cluster-issuer` annotation pointing to the same certificate, a conflict occurs.
+
+**Solution**: This overlay uses a `primary: true` flag on routes. Only the primary route's Ingress gets the `cert-manager.io/cluster-issuer` annotation. Other ingresses reference the TLS secret but don't trigger certificate creation.
+
+```yaml
+ingressAuthzOverlay:
+  routes:
+    workflows:
+      enabled: true
+      primary: true  # Only this route has cert-manager.io/cluster-issuer annotation
+      # ...
+    applications:
+      enabled: true
+      # primary: false (default) - uses the TLS secret but doesn't trigger cert creation
+```
+
+By default, the `workflows` route is primary. To change:
+
+```yaml
+ingressAuthzOverlay:
+  routes:
+    workflows:
+      primary: false
+    api:
+      primary: true  # Move certificate ownership to /api route
+```
+
 ### Configuration Options
 
 | Setting | Description | Default |
diff --git a/helm/argo-stack/overlays/ingress-authz-overlay/templates/ingress-authz.yaml b/helm/argo-stack/overlays/ingress-authz-overlay/templates/ingress-authz.yaml
index 6f81fae3..a056aef2 100644
--- a/helm/argo-stack/overlays/ingress-authz-overlay/templates/ingress-authz.yaml
+++ b/helm/argo-stack/overlays/ingress-authz-overlay/templates/ingress-authz.yaml
@@ -3,6 +3,11 @@ Ingress resources for each route in the ingress-authz-overlay.
 Each route creates a separate Ingress resource in its respective namespace,
 all sharing the same host and TLS configuration.
 All routes are protected by the authz-adapter via NGINX external auth.
+
+NOTE: Only the route with primary: true should have the cert-manager.io/cluster-issuer
+annotation. Other routes just reference the TLS secret without the annotation to avoid
+cert-manager ownership conflicts. If no route has primary: true, no ingress will have
+the cluster-issuer annotation (the Certificate must be created manually or by another means).
 */}}
 {{- if .Values.ingressAuthzOverlay.enabled }}
 {{- $root := . }}
@@ -25,8 +30,8 @@ metadata:
     meta.helm.sh/release-namespace: {{ $root.Release.Namespace }}
     # NGINX external auth annotations
     {{- include "ingress-authz-overlay.authAnnotations" $root | nindent 4 }}
-    {{- if $config.tls.enabled }}
-    # Let's Encrypt / cert-manager integration
+    {{- if and $config.tls.enabled $route.primary }}
+    # Let's Encrypt / cert-manager integration (only on primary route to avoid ownership conflicts)
     cert-manager.io/cluster-issuer: {{ $config.tls.clusterIssuer | quote }}
     {{- end }}
     {{- if $route.useRegex }}
diff --git a/helm/argo-stack/overlays/ingress-authz-overlay/values.yaml b/helm/argo-stack/overlays/ingress-authz-overlay/values.yaml
index ed3b71a4..301e2056 100644
--- a/helm/argo-stack/overlays/ingress-authz-overlay/values.yaml
+++ b/helm/argo-stack/overlays/ingress-authz-overlay/values.yaml
@@ -87,10 +87,17 @@ ingressAuthzOverlay:
   # Each route creates a separate Ingress resource in the specified namespace.
   # All routes share the same host and TLS configuration.
   # All routes are protected by the authz-adapter via NGINX external auth.
+  #
+  # IMPORTANT: Only ONE route should have the cert-manager.io/cluster-issuer annotation
+  # to avoid "certificate resource is not owned by this object" errors.
+  # Set `primary: true` on exactly one route to designate it as the certificate owner.
   routes:
-    # Argo Workflows UI
+    # Argo Workflows UI (primary route - manages TLS certificate)
     workflows:
       enabled: true
+      # Set primary: true to designate this route as the certificate owner
+      # Only the primary route gets the cert-manager.io/cluster-issuer annotation
+      primary: true
       namespace: argo-stack
       service: argo-stack-argo-workflows-server
       port: 2746