Use lineinfile properly :)

playbook/roles/erp5-standalone/tasks/main.yml

@@ -19,8 +19,10 @@
     copy: src=erp5-startup dest=/usr/local/bin/erp5-startup mode=755
   
   - name: Add to rc.local
-    lineinfile: dest=/etc/rc.local insertbefore=BOF line='bash /usr/local/bin/erp5-startup &'
-    when: grep -Fxq "/usr/local/bin/erp5-startup" /etc/rc.local == 0
+    lineinfile: 
+      dest=/etc/rc.local insertbefore=BOF 
+      line='bash /usr/local/bin/erp5-startup &'
+      state=present
 
   - name: Get slapos.playbook directory name
     shell: cd /tmp/tmpplaybookerp5-standalone.*/slapos.playbook.git/playbook/; echo $(pwd)/