For example, you have Event class and its subclass AEvent. You declare AEvent as @role( event ) with @expires

declare AEvent
   @role( event )
   @timestamp( eventTimestamp )
   @expires(3d)
end;

You have a rule for AEvent but also a rule for the super class, Event.

rule "detect AEvent"
when $e: AEvent()
then
    System.out.println("detect AEvent");
end

rule "detect Event"
when $e: Event()
then
   System.out.println("detect Event");
end

In this case, ObjectTypeNode are created for those classes. For Event, it's ObjectTypeNode.expirationOffset is -1 (because @expires is not defined). But when you trigger KieContainer.updateToVersion(), the ObjectTypeNode.expirationOffset is overwritten by AEvent's ObjectTypeNode.expirationOffset (= 3 day).