FastBoot error when passing an object property to Firestore API

[mikkopaderes]

This is an error that predates Firebase v9. Here's the sample error message.

FirebaseError: Function WriteBatch.set() called with invalid data. Data must be an object, but it was: a custom Object object (found in document posts/6JVE00WfDexhSPfXQGvu)

This happens whenever we pass in an object or array to any Firestore API. Like this:

this.store.createRecord('post', { title: 'Test title' }).save();

// Equivalent Firestore API
firestore.collection('posts').add({ title: 'Test title' });

Nuxt Firebase seems to have the same issue but they have a workaround for it. I'm not sure if there's an equivalent setting of the Nuxt.js workaround in FastBoot—I haven't found one right now.

Things I've tried so far was to disable the object and array prototype extensions but those didn't fix the issue.