diff --git a/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/porter.yaml b/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/porter.yaml
index c6b001607..a8e04193e 100644
--- a/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/porter.yaml
+++ b/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/porter.yaml
@@ -1,7 +1,7 @@
 ---
 schemaVersion: 1.0.0
 name: tre-service-guacamole-linuxvm
-version: 1.2.7
+version: 1.2.8
 description: "An Azure TRE User Resource Template for Guacamole (Linux)"
 dockerfile: Dockerfile.tmpl
 registry: azuretre
diff --git a/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/terraform/locals.tf b/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/terraform/locals.tf
index f178c0410..c304adb75 100644
--- a/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/terraform/locals.tf
+++ b/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/terraform/locals.tf
@@ -10,12 +10,7 @@ locals {
   admin_username = (
     length(data.azuread_user.user.mail) > 0 && strcontains(data.azuread_user.user.user_principal_name, "#EXT#") ?
     substr(element(split("@", data.azuread_user.user.mail), 0), 0, 20) :
-    substr(
-      strcontains(element(split("@", data.azuread_user.user.user_principal_name), 0), "#EXT#") ?
-      element(split("#EXT#", element(split("@", data.azuread_user.user.user_principal_name), 0)), 0) :
-      element(split("@", data.azuread_user.user.user_principal_name), 0),
-      0, 20
-    )
+    substr(element(split("#EXT#", element(split("@", data.azuread_user.user.user_principal_name), 0)), 0), 0, 20)
   )
   vm_password_secret_name = "${local.vm_name}-admin-credentials"
   tre_user_resources_tags = {
diff --git a/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/porter.yaml b/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/porter.yaml
index c9b6f2183..79c06e529 100644
--- a/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/porter.yaml
+++ b/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/porter.yaml
@@ -1,7 +1,7 @@
 ---
 schemaVersion: 1.0.0
 name: tre-service-guacamole-windowsvm
-version: 1.2.9
+version: 1.2.10
 description: "An Azure TRE User Resource Template for Guacamole (Windows 10)"
 dockerfile: Dockerfile.tmpl
 registry: azuretre
diff --git a/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/terraform/locals.tf b/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/terraform/locals.tf
index e9316dbeb..713db2d05 100644
--- a/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/terraform/locals.tf
+++ b/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/terraform/locals.tf
@@ -10,12 +10,7 @@ locals {
   admin_username = (
     length(data.azuread_user.user.mail) > 0 && strcontains(data.azuread_user.user.user_principal_name, "#EXT#") ?
     substr(element(split("@", data.azuread_user.user.mail), 0), 0, 20) :
-    substr(
-      strcontains(element(split("@", data.azuread_user.user.user_principal_name), 0), "#EXT#") ?
-      element(split("#EXT#", element(split("@", data.azuread_user.user.user_principal_name), 0)), 0) :
-      element(split("@", data.azuread_user.user.user_principal_name), 0),
-      0, 20
-    )
+    substr(element(split("#EXT#", element(split("@", data.azuread_user.user.user_principal_name), 0)), 0), 0, 20)
   )
   vm_password_secret_name = "${local.vm_name}-admin-credentials"
   tre_user_resources_tags = {