How do you start Task Service?
I can say only what Demian already mentioned, jbpm-human-task*.jar contains persistence xml that has "hibernate.hbm2ddl.auto" property set to create. That is the default one. Did you modify that persistence configuration of task service to point out to your Oracle db too?
Since jBPM and Task Service are two separate instances they do not share the same persistence configuration. As it goes for console, it uses TaskClient to connect to TaskService so in fact they are independent.