Buffered properties are not refreshing on Ember 3.13

[tniezurawski]

We use this addon a lot in our project. Thanks for making it happen 🙌

When upgrading to Ember 3.13 we realized that buffered properties are not getting refreshed on views when we modify them.

Consider example:

// application.js

let user = {
  firstName: 'stefan',
  email: 'example@example.com'
};

let buffer = BufferedProxy.create({
  content: user
});

{{!-- application.hbs --}}

<div>{{buffer.firstName}}</div>

{{input value=buffer.firstName onChange=(action (mut buffer.firstName))}}

When we change the value in input then the value in the <div> should be updated. It works properly on Ember 3.12 but fails on Ember 3.13. Something had to change around tracked properties IMO but I'm not sure exactly what.

Anyway, the fix is really a one-liner. But it would be great to understand the impact of this change.