Putting entries with memcached is ignoring the queue-flush-interval parameter

<replicated-cache name="memcachedCache"
    start="EAGER"
    mode="ASYNC"
    batching="false"                    
    queue-size="1000"
    queue-flush-interval="15000">
</replicated-cache>

mc1 = new MemcachedHelper(server1.getMemcachedEndpoint().getInetAddress().getHostName(), server1.getMemcachedEndpoint().getPort());
mc2 = new MemcachedHelper(server2.getMemcachedEndpoint().getInetAddress().getHostName(), server2.getMemcachedEndpoint().getPort());
mc1.set("key1", "value1");
assertTrue(null != mc1.get("key1"));
assertTrue(null == mc2.get("key1"));