Hazelcast write-behind with map.replace - hazelcast

Question

It seems that the MapStore (write-behind mode) does not work properly when replacing some map items.
I expected that map items which have been replaced, are not processed anymore.
I am using Hazelcast 3.2.5
Did i miss something here?
Please see Server Test Class, Client Test Class and Output as well to demonstrate the problem.
Server Class:
public class HazelcastInstanceTest {
public static void main(String[] args) {
Config cfg = new Config();
MapConfig mapConfig = new MapConfig();
MapStoreConfig mapStoreConfig = new MapStoreConfig();
mapStoreConfig.setEnabled(true);
mapStoreConfig.setClassName("com.test.TestMapStore");
mapStoreConfig.setWriteDelaySeconds(15);
mapConfig.setMapStoreConfig(mapStoreConfig);
mapConfig.setName("customers");
cfg.addMapConfig(mapConfig);
HazelcastInstance instance = Hazelcast.newHazelcastInstance(cfg);
}
}
MapStore Impl Class
public class TestMapStore implements MapStore {
#Override
public Object load(Object arg0) {
System.out.println("--> LOAD");
return null;
}
#Override
public Map loadAll(Collection arg0) {
System.out.println("--> LOAD ALL");
return null;
}
#Override
public Set loadAllKeys() {
System.out.println("--> LOAD ALL KEYS");
return null;
}
#Override
public void delete(Object arg0) {
System.out.println("--> DELETE");
}
#Override
public void deleteAll(Collection arg0) {
System.out.println("--> DELETE ALL");
}
#Override
public void store(Object arg0, Object arg1) {
System.out.println("--> STORE " + arg1.toString());
}
#Override
public void storeAll(Map arg0) {
System.out.println("--> STORE ALL");
}
}
Client Class
public class HazelcastClientTest {
public static void main(String[] args) throws Exception {
ClientConfig clientConfig = new ClientConfig();
HazelcastInstance client = HazelcastClient.newHazelcastClient(clientConfig);
IMap mapCustomers = client.getMap("customers");
System.out.println("Map Size:" + mapCustomers.size());
mapCustomers.put(1, "Item A");
mapCustomers.replace(1, "Item B");
mapCustomers.replace(1, "Item C");
System.out.println("Map Size:" + mapCustomers.size());
}
}
Client Output (which is ok):
Map Size:0
Map Size:1
Server Output (which is not ok, as i suppose. I expected only item C)
--> LOAD ALL KEYS
--> LOAD
--> STORE Item A
--> STORE ALL
--> STORE Item B
--> STORE Item C
Any help is appreciate.
Many thanks