Playbook wasn't using then user variable to format the command.

ksetup/tasks_end.yaml

@@ -1,6 +1,6 @@
 # https://stackoverflow.com/questions/46515704/how-to-kill-a-running-process-using-ansible
 - name: Get running processes
-  shell: "ps -ef | grep -v grep | grep -w ^orangepi | awk '{print $2}'"
+  shell: "ps -ef | grep -v grep | grep -w ^{{ orangepi }} | awk '{print $2}'"
   register: running_processes
   when: delete_user_name is defined and delete_user_name | length > 0