in v0.12 https://github.com/bitcoin/bitcoin/pull/7081 (by @luke-jr) was merged adding `-bytespersigop` (with default of 20).

this is preventing simple bare multisig transactions from being accepted into mempool when the size is < 400 bytes.  
eg; https://gist.github.com/rubensayshi/ac4f617207f7a50559e85d61c05800be

from 1-of-7 and onwards they are accepted because the ratio of bytes:sigops is high enough.  
also having 2 or more inputs will work because it again tips the ratio of bytes:sigops over.

the reason mainly being that `GetLegacySigOpCount` calls `GetSigOpCount` with `fAccurate=false`.

It looks like changing `GetLegacySigOpCount` to use `fAccurate=true` would cause side effects in the few other places (`ConnectBlock`, `CheckBlock`, `CreateNewBlock`) and simply adding `fAccurate` as arg to `GetLegacySigOpCount` would affect the value stored in `CTxMemPoolEntry.sigOpCount` which in turn affects a bunch of other things.

pwalletMain->Flush(false);
#endif
    StopNode();
    StopTorControl();
    UnregisterNodeSignals(GetNodeSignals());
    if (fFeeEstimatesInitialized)
    {
        boost::filesystem::path est_path = GetDataDir() / FEE_ESTIMATES_FILENAME;
        CAutoFile est_fileout(fopen(est_path.string().c_str(), "wb"), SER_DISK, CLIENT_VERSION);
        if (!est_fileout.IsNull())
            mempool.WriteFeeEstimates(est_fileout);
        else
            LogPrintf("%s: Failed to write fee estimates to %s\n", __func__, est_path.string());
        fFeeEstimatesInitialized = false;
    }
    {
        LOCK(cs_main);
        if (pcoinsTip != NULL) {
            FlushStateToDisk();
        }
        delete pcoinsTip;
        pcoinsTip = NULL;
        delete pcoinscatcher;
        pcoinscatcher = NULL;
        delete pcoinsdbview;
        pcoinsdbview = NULL;
        delete pblocktree;
        pblocktree = NULL;
    }
#ifdef ENABLE_WALLET