alert_text not printing some arguments, Am i missing something ?

[vik2595]

My test.yml

alert_subject: "Kibana Test alert {0} | {1} | {2} | {3}"
alert_subject_args: ["context.agent.name", "context.agent.id", "@timestamp", "_index"]

alert_text: |-
  Kibana visitor extented to {0} | {1}.
  Please close your session if you're not using it.

alert_text_args: ["system.socket.summary.tcp.all.established","system.socket.summary.tcp.all.established"]

Output:

Kibana Test alert  |  | 2021-03-31T13:54:29.109Z | metricbeat-7.12.0-2021.03.29-000001

Kibana visitor extended to  | .
Please close your session if you're not using it.

what would be the argument structure?