archaius-core/src/main/java/com/netflix/config/util/ConfigurationUtils.java
@Override
    public void addProperty(String name, Object value) {
        if (containsKey(name)) {
            // clear without triggering an event
            clearPropertyDirect(name);
        }
        super.addProperty(name, value);        
    }
@Override
    public void addProperty(String name, Object value) {
        if (containsKey(name)) {
            // clear without triggering an event
            clearPropertyDirect(name);
        }
        super.addProperty(name, value);        
    }
Need to override this method for PDCLOUD-1809.