do you change your configMap manually? how do you install the operator into your cluster? how is the operator webhook configured? can you list all settings you defined? what is operator version?

when you asked it restart sometimes do you mean K8sDeployment restarts ? - in this case it is totally normal and your job should take state of your previous job (of course if you set property job.upgradeMode = 'last-state') unless you mean FlinkDeployment restarts - in this case it is treated as a newly created job.