To reproduce,

1. Build the openflowplugin distribution
2. Enable clustering by renaming configuration/initial/05-clustering.xml.conf to configuration/initial/05-clustering.xml
3. In logback.xml enable the InventoryManager logging as follows,
<logger name="org.opendaylight.controller.md.inventory.manager" level="DEBUG"/>
4. Run the controller with these options
./run.sh -XX:MaxPerSize=512m -Xmx4G
5. Run a mininet against the controller with the command
sudo mn --controller=remote,ip=<ipaddress> --topo tree,4

Using restconf check if the complete inventory has been populated. You may find that it is not populated. If not check for the inventory manager log to see if the notification actually reached it. You will find that it did not.

Subsequently if you disconnect mininet from the controller you may also find that that NodeRemoved events are also not being generated.