https://travis-ci.org/github/bitcoin/bitcoin/jobs/679885530#L8791
if (IsCurrentForAntiFeeSniping(chain, block_hash)) {
        locktime = block_height;
        
        
        
        
        if (GetRandInt(10) == 0)
            locktime = std::max(0, (int)locktime - GetRandInt(100));
    } else {
        
        
        
        locktime = 0;
    }
    assert(locktime < LOCKTIME_THRESHOLD);
    return locktime;
}
OutputType CWallet::TransactionChangeType(const Optional<OutputType>& change_type, const std::vector<CRecipient>& vecSend) const