update..

roles/common/tasks/nis-install-client.yml

@@ -179,7 +179,7 @@
 - name: (nis-install-client.yml) Adjust file /etc/nsswitch.conf (set hosts)
   replace:
     path: /etc/nsswitch.conf
-    regexp: '(hosts:\s+files)\s+([^nis].*)'
+    regexp: '(hosts:\s+files)\s+((?!nis).*)$'
     replace: '\1 nis \2'
   tags:
     - nis-install
@@ -188,7 +188,7 @@
 - name: (nis-install-client.yml) Adjust file /etc/nsswitch.conf (set passwd/group/shadow)
   replace:
     path: /etc/nsswitch.conf
-    regexp: '^({{ item }}:\s+.*)'
+    regexp: '^({{ item }}:\s+((?!nis).)*)$'
     replace: '\1 nis'
   with_items:
      - passwd