As segwit is active on testnet, blocks will only be downloaded from NODE_WITNESS peers. Though, exactly those peers are disconnected after `BLOCK_STALLING_TIMEOUT = 2` seconds. I am running master (6e6ab2c)

This behavior is consistent across restarts. Sample [debug.log](http://pastebin.ubuntu.com/23058327/) and [getchaintips](http://pastebin.ubuntu.com/23058325/).

It is possible that I shot my own foot at some point, but it seemed smelly enough to create an issue.

CheckBlockIndex(chainparams.GetConsensus());
    }
    else if (strCommand == NetMsgType::BLOCKTXN && !fImporting && !fReindex) 
    {
        BlockTransactions resp;
        vRecv >> resp;
        LOCK(cs_main);
        map<uint256, pair<NodeId, list<QueuedBlock>::iterator> >::iterator it = mapBlocksInFlight.find(resp.blockhash);
        if (it == mapBlocksInFlight.end() || !it->second.second->partialBlock ||
                it->second.first != pfrom->GetId()) {
            LogPrint("net", "Peer %d sent us block transactions for block we weren't expecting\n", pfrom->id);
            return true;
        }
        PartiallyDownloadedBlock& partialBlock = *it->second.second->partialBlock;
        CBlock block;
        ReadStatus status = partialBlock.FillBlock(block, resp.txn);
        if (status == READ_STATUS_INVALID) {
            MarkBlockAsReceived(resp.blockhash); 
            Misbehaving(pfrom->GetId(), 100);
            LogPrintf("Peer %d sent us invalid compact block/non-matching block transactions\n", pfrom->id);
            return true;
        } else if (status == READ_STATUS_FAILED) {
            
            std::vector<CInv> invs;
            invs.push_back(CInv(MSG_BLOCK, resp.blockhash));
            pfrom->PushMessage(NetMsgType::GETDATA, invs);
        } else {
            CValidationState state;
            ProcessNewBlock(state, chainparams, pfrom, &block, false, NULL);
            int nDoS;