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.
CKeyID master_id = masterKey.key.GetPubKey().GetID();
            std::copy(master_id.begin(), master_id.begin() + 4, meta.key_origin.fingerprint);
            if (!ParseHDKeypath(meta.hdKeypath, meta.key_origin.path)) {
                throw std::runtime_error("Invalid stored hdKeypath");
            }
            meta.has_key_origin = true;
            if (meta.nVersion < CKeyMetadata::VERSION_WITH_KEY_ORIGIN) {
                meta.nVersion = CKeyMetadata::VERSION_WITH_KEY_ORIGIN;
            }
            
            CPubKey pubkey;
            if (GetPubKey(meta_pair.first, pubkey)) {
                batch->WriteKeyMetadata(meta, pubkey, true);
            }
        }
    }
}
bool LegacyScriptPubKeyMan::SetupGeneration(bool force)
{
    if ((CanGenerateKeys() && !force) || m_storage.IsLocked()) {
        return false;
    }
    SetHDSeed(GenerateNewSeed());
    if (!NewKeyPool()) {
        return false;
    }
    return true;
}
bool LegacyScriptPubKeyMan::IsHDEnabled() const