Configuration.clearProperty() does not work for multilevel subsets

@Inject 
Configuration config;

@Inject
@Subset("subset.subset")
private Configuration subSubsetConfiguration;

@Test
public void testSubSubsetConfigurationClearProperty() throws Exception
{
   configuration.clear();
   configuration.setProperty("subset.subset.A", "Value");
   assertTrue(subSubsetConfiguration.getKeys().hasNext());
   subSubsetConfiguration.clearProperty("A");
   assertFalse(subSubsetConfiguration.getKeys().hasNext());
   assertFalse(configuration.getKeys().hasNext());
}