When running walletpassphrase on a large wallet.dat (ie about 300,000 segwit P2SH addresses) the command sometimes takes a very long time, and if command is run multiple times at once (while running slow) it causes bitcoin core to freeze (stops syncing and requires kill -9 to stop/restart)

During the locked up walletpassphrase commands being run the following messages start to appear in the debug.log:

`018-01-24 01:01:04 socket sending timeout: 1201s`

Note that this problem is intermittent, so sometimes the command runs instantly, other times it takes a few minutes, and other times it completely freezes the node.
{
    LOCK(cs_KeyStore);
    return (!setWatchOnly.empty());
}
static bool ExtractPubKey(const CScript &dest, CPubKey& pubKeyOut)
{
    std::vector<std::vector<unsigned char>> solutions;
    return Solver(dest, solutions) == TX_PUBKEY &&
        (pubKeyOut = CPubKey(solutions[0])).IsFullyValid();
}
bool LegacyScriptPubKeyMan::RemoveWatchOnly(const CScript &dest)
{
    {
        LOCK(cs_KeyStore);
        setWatchOnly.erase(dest);
        CPubKey pubKey;
        if (ExtractPubKey(dest, pubKey)) {
            mapWatchKeys.erase(pubKey.GetID());
        }
        
        
    }
    if (!HaveWatchOnly())
        NotifyWatchonlyChanged(false);
    if (!WalletBatch(m_storage.GetDatabase()).EraseWatchOnly(dest))
        return false;
    return true;
}
bool LegacyScriptPubKeyMan::LoadWatchOnly(const CScript &dest)