Issue can be simulated on Tomcat server.
If Kie server has activated policies (i.e. KeepLatestContainerOnlyPolicy) and user try to stop whole server then server process is not completely stopped - process is still running.

It seems to be caused by scheduledExecutorService in PolicyManager. This scheduler is not closed when stopping policy manager. This is ok for other containers as they used DefaultManagedScheduledExecutorService from context, but Tomcat uses standard java executor.