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.

!std::equal(expect.begin(), expect.end(), block.vtx[0].vin[0].scriptSig.begin())) {
            return state.DoS(100, false, REJECT_INVALID, "bad-cb-height", false, "block height mismatch in coinbase");
        }
    }
    
    
    
    
    
    
    
    
    bool fHaveWitness = false;
    if (VersionBitsState(pindexPrev, consensusParams, Consensus::DEPLOYMENT_SEGWIT, versionbitscache) == THRESHOLD_ACTIVE) {
        int commitpos = GetWitnessCommitmentIndex(block);
        if (commitpos != -1) {
            bool malleated = false;
            uint256 hashWitness = BlockWitnessMerkleRoot(block, &malleated);
            
            
            
            if (block.vtx[0].wit.vtxinwit.size() != 1 || block.vtx[0].wit.vtxinwit[0].scriptWitness.stack.size() != 1 || block.vtx[0].wit.vtxinwit[0].scriptWitness.stack[0].size() != 32) {
                return state.DoS(100, false, REJECT_INVALID, "bad-witness-nonce-size", true, strprintf("%s : invalid witness nonce size", __func__));
            }
            CHash256().Write(hashWitness.begin(), 32).Write(&block.vtx[0].wit.vtxinwit[0].scriptWitness.stack[0][0], 32).Finalize(hashWitness.begin());
            if (memcmp(hashWitness.begin(), &block.vtx[0].vout[commitpos].scriptPubKey[6], 32)) {
                return state.DoS(100, false, REJECT_INVALID, "bad-witness-merkle-match", true, strprintf("%s : witness merkle commitment mismatch", __func__));
            }
            fHaveWitness = true;
        }