update..

roles/common/templates/etc/sudoers.d/50-user.j2

@@ -36,6 +36,11 @@ back {{ item }}
 {% endfor -%}
 
 
+{%- for item in sudoers_file_user_back_mount_privileges | default([]) %}
+back {{ item }}
+{% endfor -%}
+
+
 {%- if ansible_virtualization_role == 'host' %}
 
 {% for item in sudoers_file_user_back_disk_privileges | default([]) %}