Node.js redis@4 Upgrade: SocketClosedUnexpectedlyError: Socket closed unexpectedly

I've got some legacy code that I'm upgrading from version 3 of the Node.js redis library to version 4 of the Node.js redis library. The basic shape of the code looks like this

var redis = require('redis')
var client = redis.createClient({
    port: '6379',
    host: process.env.REDIS_HOST,
    legacyMode: true
})
client.connect()
client.flushall(function (err, reply) {
    client.hkeys('hash key', function (err, replies) {
      console.log("key set done")
      client.quit()
    })
})
console.log("main done")

When I run this code with redis@4.3.1, I get the following error, and node.js exits with a non-zero status code

main done
key set done
events.js:292
      throw er; // Unhandled 'error' event
      ^

SocketClosedUnexpectedlyError: Socket closed unexpectedly
    at Socket.<anonymous> (/Users/astorm/Documents/redis4/node_modules/@redis/client/dist/lib/client/socket.js:182:118)
    at Object.onceWrapper (events.js:422:26)
    at Socket.emit (events.js:315:20)
    at TCP.<anonymous> (net.js:673:12)
Emitted 'error' event on Commander instance at:
    at RedisSocket.<anonymous> (/Users/astorm/Documents/redis4/node_modules/@redis/client/dist/lib/client/index.js:350:14)
    at RedisSocket.emit (events.js:315:20)
    at RedisSocket._RedisSocket_onSocketError (/Users/astorm/Documents/redis4/node_modules/@redis/client/dist/lib/client/socket.js:205:10)
    at Socket.<anonymous> (/Users/astorm/Documents/redis4/node_modules/@redis/client/dist/lib/client/socket.js:182:107)
    at Object.onceWrapper (events.js:422:26)
    at Socket.emit (events.js:315:20)
    at TCP.<anonymous> (net.js:673:12)
 

While in redis@3.1.2 it runs (minus the client.connect()) without issue.

I've been able to work around this by replacing client.quit() with client.disconnect(), but the actual code is a little more complex than the above example and I'd rather use the graceful shutdown of client.quit than the harsher "SHUT IT DOWN NOW" of client.disconnect().

Does anyone know what the issue here might be? Why is redis@4 failing with a SocketClosedUnexpectedlyError: Socket closed unexpectedly error.