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.
{
    return EraseIC(std::make_pair(DBKeys::PURPOSE, strAddress));
}
bool WalletBatch::WriteTx(const CWalletTx& wtx)
{
    return WriteIC(std::make_pair(DBKeys::TX, wtx.GetHash()), wtx);
}
bool WalletBatch::EraseTx(uint256 hash)
{
    return EraseIC(std::make_pair(DBKeys::TX, hash));
}
bool WalletBatch::WriteKeyMetadata(const CKeyMetadata& meta, const CPubKey& pubkey, const bool overwrite)
{
    return WriteIC(std::make_pair(DBKeys::KEYMETA, pubkey), meta, overwrite);
}
bool WalletBatch::WriteKey(const CPubKey& vchPubKey, const CPrivKey& vchPrivKey, const CKeyMetadata& keyMeta)
{
    if (!WriteKeyMetadata(keyMeta, vchPubKey, false)) {
        return false;
    }
    
    std::vector<unsigned char> vchKey;
    vchKey.reserve(vchPubKey.size() + vchPrivKey.size());
    vchKey.insert(vchKey.end(), vchPubKey.begin(), vchPubKey.end());
    vchKey.insert(vchKey.end(), vchPrivKey.begin(), vchPrivKey.end());
    return WriteIC(std::make_pair(DBKeys::KEY, vchPubKey), std::make_pair(vchPrivKey, Hash(vchKey.begin(), vchKey.end())), false);
}
bool WalletBatch::WriteCryptedKey(const CPubKey& vchPubKey,