From kubernetes docs if I have a Cronjob that is executed each day at 00:00 say, and should only run once, the job template should have these fields:
.spec.concurrencyPolicy: Replace
.spec.completions: 1
.spec.parallelism: 1
However, the job is being executed sometimes more than once, but now always, and this cases, the job is not failing either, and it successfully terminates.