diff --git a/common/deploy-steps.j2 b/common/deploy-steps.j2
index 49e5ec1750..ac5d0bf69d 100644
--- a/common/deploy-steps.j2
+++ b/common/deploy-steps.j2
@@ -274,65 +274,50 @@ resources:
     properties:
       type: comma_delimited_list
       value:
-        yaql:
-          # processing from per-role unique tasks into globally unique tasks
-          expression: coalesce($.data, []).flatten().distinct()
-          data:
-          {%- for role in enabled_roles %}
-            - get_param: [role_data, {{role.name}}, external_deploy_tasks]
-          {%- endfor %}
+        list_concat_unique:
+        {%- for role in enabled_roles %}
+          - get_param: [role_data, {{role.name}}, external_deploy_tasks]
+        {%- endfor %}
 
   ExternalPostDeployTasks:
     type: OS::Heat::Value
     properties:
       type: comma_delimited_list
       value:
-        yaql:
-          # processing from per-role unique tasks into globally unique tasks
-          expression: coalesce($.data, []).flatten().distinct()
-          data:
-          {%- for role in enabled_roles %}
-            - get_param: [role_data, {{role.name}}, external_post_deploy_tasks]
-          {%- endfor %}
+        list_concat_unique:
+        {%- for role in enabled_roles %}
+          - get_param: [role_data, {{role.name}}, external_post_deploy_tasks]
+        {%- endfor %}
 
   ScaleTasks:
     type: OS::Heat::Value
     properties:
       type: comma_delimited_list
       value:
-        yaql:
-          # processing from per-role unique tasks into globally unique tasks
-          expression: coalesce($.data, []).flatten().distinct()
-          data:
-          {%- for role in enabled_roles %}
-            - get_param: [role_data, {{role.name}}, scale_tasks]
-          {%- endfor %}
+        list_concat_unique:
+        {%- for role in enabled_roles %}
+          - get_param: [role_data, {{role.name}}, scale_tasks]
+        {%- endfor %}
 
   ExternalUpdateTasks:
     type: OS::Heat::Value
     properties:
       type: comma_delimited_list
       value:
-        yaql:
-          # processing from per-role unique tasks into globally unique tasks
-          expression: coalesce($.data, []).flatten().distinct()
-          data:
-          {%- for role in enabled_roles %}
-            - get_param: [role_data, {{role.name}}, external_update_tasks]
-          {%- endfor %}
+        list_concat_unique:
+        {%- for role in enabled_roles %}
+          - get_param: [role_data, {{role.name}}, external_update_tasks]
+        {%- endfor %}
 
   ExternalUpgradeTasks:
     type: OS::Heat::Value
     properties:
       type: comma_delimited_list
       value:
-        yaql:
-          # processing from per-role unique tasks into globally unique tasks
-          expression: coalesce($.data, []).flatten().distinct()
-          data:
-          {%- for role in enabled_roles %}
-            - get_param: [role_data, {{role.name}}, external_upgrade_tasks]
-          {%- endfor %}
+        list_concat_unique:
+        {%- for role in enabled_roles %}
+          - get_param: [role_data, {{role.name}}, external_upgrade_tasks]
+        {%- endfor %}
 
   BootstrapServerId:
     type: OS::Heat::Value