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.

}
/**
 * Calculates the block height and previous block's median time past at
 * which the transaction will be considered final in the context of BIP 68.
 * Also removes from the vector of input heights any entries which did not
 * correspond to sequence locked inputs as they do not affect the calculation.
 */
static std::pair<int, int64_t> CalculateSequenceLocks(const CTransaction &tx, int flags, std::vector<int>* prevHeights, const CBlockIndex& block)
{
    assert(prevHeights->size() == tx.vin.size());
    
    
    
    
    
    int nMinHeight = -1;
    int64_t nMinTime = -1;
    
    
    
    bool fEnforceBIP68 = static_cast<uint32_t>(tx.nVersion) >= 2
                      && flags & LOCKTIME_VERIFY_SEQUENCE;
    
    
    if (!fEnforceBIP68) {
        return std::make_pair(nMinHeight, nMinTime);
    }
    for (size_t txinIndex = 0; txinIndex < tx.vin.size(); txinIndex++) {
        const CTxIn& txin = tx.vin[txinIndex];