With the default inbox and task details view, there is a finishURL. The completeTask method should have a snippet that refers to the finishUrl:
...
// then redirect to finish url
String url = getCustomAssignmentTaskView().getFinishUrl();
if (url != null && url.length() > 0) {
getFacesContext().getExternalContext().redirect(url);
}
Do you know if the creation or usage of the finishUrl was modified at all?
#webMethods-BPMS#MWS-CAF-Task-Engine#webMethods