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.
#include <key_io.h>
#include <outputtype.h>
#include <script/descriptor.h>
#include <script/sign.h>
#include <util/bip32.h>
#include <util/strencodings.h>
#include <util/string.h>
#include <util/translation.h>
#include <wallet/scriptpubkeyman.h>
bool LegacyScriptPubKeyMan::GetNewDestination(const OutputType type, CTxDestination& dest, std::string& error)