A potential problem in the Ec2MultiRegionSnitch_gossiperStarting method

    public void gossiperStarting()
    {
        super.gossiperStarting();
        Gossiper.instance.addLocalApplicationState(ApplicationState.INTERNAL_IP, StorageService.instance.valueFactory.internalIP(localPrivateAddress));
        Gossiper.instance.register(new ReconnectableSnitchHelper(this, ec2region, true));
    }

public void gossiperStarting()
    {
        super.gossiperStarting();

        Gossiper.instance.addLocalApplicationState(ApplicationState.INTERNAL_IP,
                StorageService.instance.valueFactory.internalIP(FBUtilities.getLocalAddress().getHostAddress()));

        reloadGossiperState();

        gossipStarted = true;
    }

    private void reloadGossiperState()
    {
        if (Gossiper.instance != null)
        {
            ReconnectableSnitchHelper pendingHelper = new ReconnectableSnitchHelper(this, myDC, preferLocal);
            Gossiper.instance.register(pendingHelper);
            
            pendingHelper = snitchHelperReference.getAndSet(pendingHelper);
            if (pendingHelper != null)
                Gossiper.instance.unregister(pendingHelper);
        }
        // else this will eventually rerun at gossiperStarting()
    }