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.
bool TopUp(unsigned int size = 0) override;
    void MarkUnusedAddresses(const CScript& script) override;
    bool IsHDEnabled() const override;
    
    bool SetupDescriptorGeneration(const CExtKey& master_key);
    bool HavePrivateKeys() const override;
    int64_t GetOldestKeyPoolTime() const override;
    size_t KeypoolCountExternalKeys() const override;
    unsigned int GetKeyPoolSize() const override;
    int64_t GetTimeFirstKey() const override;
    std::unique_ptr<CKeyMetadata> GetMetadata(const CTxDestination& dest) const override;
    bool CanGetAddresses(bool internal = false) const override;
    std::unique_ptr<SigningProvider> GetSolvingProvider(const CScript& script) const override;
    bool CanProvide(const CScript& script, SignatureData& sigdata) override;
    bool SignTransaction(CMutableTransaction& tx, const std::map<COutPoint, Coin>& coins, int sighash, std::map<int, std::string>& input_errors) const override;
    SigningResult SignMessage(const std::string& message, const PKHash& pkhash, std::string& str_sig) const override;
    TransactionError FillPSBT(PartiallySignedTransaction& psbt, int sighash_type = 1 , bool sign = true, bool bip32derivs = false) const override;
    uint256 GetID() const override;
    void SetType(OutputType type, bool internal) override;
    void SetCache(const DescriptorCache& cache);
    bool AddKey(const CKeyID& key_id, const CKey& key);
    bool AddCryptedKey(const CKeyID& key_id, const CPubKey& pubkey, const std::vector<unsigned char>& crypted_key);
    bool HasWalletDescriptor(const WalletDescriptor& desc) const;
    void AddDescriptorKey(const CKey& key, const CPubKey &pubkey);
    void WriteDescriptor();
    const WalletDescriptor GetWalletDescriptor() const EXCLUSIVE_LOCKS_REQUIRED(cs_desc_man);
    const std::vector<CScript> GetScriptPubKeys() const;
};
#endif