Quote from documentation for org.opendaylight.controller.md.sal.common.api.data.AsyncDataBroker#registerDataChangeListener:

"If there is any preexisting data in data tree on path for which you are registering, you will receive initial data change event, which will contain all preexisting data, marked as created."

However DataChangeListener are not being notified of preexisting data on registration when wildcard ID is used

Version: Helium-SR4

Sample unit test attached