This is actually an issue in the pubsub-light-module. The GuavaPubsubBus does an AccessControlled check before allowing publishing of any message. The first part of that is to check for the existence of the model object associated with the event. But of course In the case of this delete event (or any other delete event), the model object no longer exists, causing the security check to fail and for the event to not be published.
Need to come up with some event specific way of indicating that it's OK to forward the event if the model object does not exist.