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 (wtx.nOrderPos == -1)
                    wss.fAnyUnordered = true;
                return true;
            };
            if (!pwallet->LoadToWallet(hash, fill_wtx)) {
                return false;
            }
        } else if (strType == DBKeys::WATCHS) {
            wss.nWatchKeys++;
            CScript script;
            ssKey >> script;
            char fYes;
            ssValue >> fYes;
            if (fYes == '1') {
                pwallet->GetOrCreateLegacyScriptPubKeyMan()->LoadWatchOnly(script);
            }
        } else if (strType == DBKeys::KEY) {
            CPubKey vchPubKey;
            ssKey >> vchPubKey;
            if (!vchPubKey.IsValid())
            {
                strErr = "Error reading wallet database: CPubKey corrupt";
                return false;
            }
            CKey key;
            CPrivKey pkey;
            uint256 hash;
            wss.nKeys++;
            ssValue >> pkey;