setApplication breaks ember-qunit test context

I recently upgraded an Ember app from 2.18 to 3.13 which went smoothly. Today I tried to add an acceptance test for the first time (only had integration / unit tests before this) but the test is failing on the first line:

import { module, test } from "qunit";
import { visit, currentURL } from "@ember/test-helpers";
import { setupApplicationTest } from "ember-qunit";

module("Acceptance | some route", function(hooks) {
  setupApplicationTest(hooks);

  test("visiting /some-route", async function(assert) {
    await visit("/some-route"); // <----- error thrown here

    assert.equal(currentURL(), "/some-route");
  });
});

I'm seeing a couple errors (in this order):

Source:     
TypeError: Cannot read property 'lookup' of undefined
    at Object.initialize (http://localhost:4200/assets/ritual-checkout.js:10312:28)
    at http://localhost:4200/assets/vendor.js:61627:21
    at Vertices.each (http://localhost:4200/assets/vendor.js:80243:9)
    at Vertices.walk (http://localhost:4200/assets/vendor.js:80157:12)
    at DAG.each (http://localhost:4200/assets/vendor.js:80087:22)
    at DAG.topsort (http://localhost:4200/assets/vendor.js:80095:12)
    at Class._runInitializer (http://localhost:4200/assets/vendor.js:61653:13)
    at Class.runInitializers (http://localhost:4200/assets/vendor.js:61625:12)
    at Class._bootSync (http://localhost:4200/assets/vendor.js:59923:14)
    at Class.boot (http://localhost:4200/assets/vendor.js:59890:14)


Source:     
Error: Cannot call `visit` without having first called `setupApplicationContext`.
    at visit (http://localhost:4200/assets/test-support.js:44177:13)
    at Object._callee$ (http://localhost:4200/assets/tests.js:23:47)
    at tryCatch (http://localhost:4200/assets/vendor.js:12365:40)
    at Generator.invoke [as _invoke] (http://localhost:4200/assets/vendor.js:12591:22)
    at Generator.prototype.<computed> [as next] (http://localhost:4200/assets/vendor.js:12417:21)
    at asyncGeneratorStep (http://localhost:4200/assets/tests.js:6:105)
    at _next (http://localhost:4200/assets/tests.js:8:196)
    at http://localhost:4200/assets/tests.js:8:366
    at new Promise (<anonymous>)
    at Object.<anonymous> (http://localhost:4200/assets/tests.js:8:99)

After a little digging, it looks like something is setting the test context incorrectly. It's just an empty object:

Thus, isApplicationTestContext(context) returns false and the second error gets thrown. I'm guessing the first error is thrown because the app has some initializers that perform lookups.

In an effort to add this acceptance test I also updated the test-helper.js file to the following:

import Application from "../app";
import config from "../config/environment";
import { setApplication } from "@ember/test-helpers";
import { start } from "ember-qunit";

setApplication(Application.create(config.APP));

start();

With the above file, all tests are failing so it seems that setApplication is causing the test context to be set incorrectly? The old test-helper.js file was like so:

import resolver from "./helpers/resolver";
import { setResolver } from "@ember/test-helpers";
import { start } from "ember-cli-qunit";

setResolver(resolver);
start();

I've tried re-adding the setResolver call but it doesn't make a difference. Has anyone else run into these issues with the new ember-qunit syntax or could maybe see what I'm doing wrong? Also, I've set autoboot = false; in the environment.js file which didn't make a difference. The test suite also has one or two tests that are still written in the older ember-qunit syntax. Any help would be appreciated!