Sorry - not having access to JIRA nor github.
termnationGracePeriodSeconds is an attribute of Statefulset of the original MongoDB distro. I assume Percona Replicaset is also based on a Statefulset … so a pass through is required.
And this param is quite important - otherwise a restart/reschedule of the pods will cause a crash of the mongodb which can lead to a very long recovery. Even worse it can totally crash the cluster if liveness probe is not configured properly.
Regards
John