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.
{
    if (!AddWatchOnlyInMem(dest))
        return false;
    const CKeyMetadata& meta = m_script_metadata[CScriptID(dest)];
    UpdateTimeFirstKey(meta.nCreateTime);
    NotifyWatchonlyChanged(true);
    if (batch.WriteWatchOnly(dest, meta)) {
        m_storage.UnsetBlankWalletFlag(batch);
        return true;
    }
    return false;
}
bool LegacyScriptPubKeyMan::AddWatchOnlyWithDB(WalletBatch &batch, const CScript& dest, int64_t create_time)
{
    m_script_metadata[CScriptID(dest)].nCreateTime = create_time;
    return AddWatchOnlyWithDB(batch, dest);
}
bool LegacyScriptPubKeyMan::AddWatchOnly(const CScript& dest)
{
    WalletBatch batch(m_storage.GetDatabase());
    return AddWatchOnlyWithDB(batch, dest);
}
bool LegacyScriptPubKeyMan::AddWatchOnly(const CScript& dest, int64_t nCreateTime)
{
    m_script_metadata[CScriptID(dest)].nCreateTime = nCreateTime;
    return AddWatchOnly(dest);
}
void LegacyScriptPubKeyMan::SetHDChain(const CHDChain& chain, bool memonly)