TypeError: Cannot read property 'INTERNAL' of undefined at FirebaseNamespace.initializeApp

[REQUIRED] Step 2: Describe your environment

• Operating System version: macOS 10.14.4 (18E226)
• Firebase SDK version: 8.2.0
• Library version: unclear what this means
• Firebase Product: initialization of admin app

[REQUIRED] Step 3: Describe the problem

Steps to reproduce:

Clone the following repository: https://github.com/liamdanielduffy/firebase-admin-bug-repro

Run npm install or yarn in the repository root. Run npm run dev or yarn dev to start the server. Visit localhost:3000/api/graphql.

See the following message printed in the server logs:

TypeError: Cannot read property 'INTERNAL' of undefined
    at FirebaseNamespace.initializeApp (.../firebase-admin-bug-repro/node_modules/firebase-admin/lib/firebase-namespace.js:392:21)
    ...(rest of stack trace)

Further context

The firebase admin SDK is being initialized in libraries/firebase/initializeAdminApp. The service account key is present in the repository, and is exported from libraries/firebase/getKey.

On each network request to localhost:3000/api/graphql, the function defined in libraries/apollo/getContext is called. This function attempts to pass the firebase app as part of the ‘context’ for all the graphql resolvers defined in libraries/nexus/schema.

I’m not sure why the error is being printed above, but the stack trace above points to this line in the firebase-admin package: firebase-admin/lib/firebase-namespace.js:392

 FirebaseNamespace.prototype.initializeApp = function (options, appName) {
        return this.INTERNAL.initializeApp(options, appName);
    };

this is undefined, creating the error thrown.

Why would that happen? Am I initializing this in the wrong way or in the wrong place?