When reloading the page, it fails to load the backup

https://user-images.githubusercontent.com/10626596/120861558-1aefaa00-c54d-11eb-99c2-92166ca84b30.mov

**Describe the bug**

When reloading a page that I have edited, it offers to load the backup of text that I hadn't saved yet, and then immediately replaces that text with the text that is saved.

**To Reproduce**

1. Open a post
2. add some new text to the body
3. reload the page
4. select "load from backup"
5. watch the new text flash onto the screen, and then the page reloads again without the new text.

**Expected behavior**

I would expect the backup to work.

**Screenshots**

**Applicable Versions:**

- Netlify CMS version: ```netlify-cms-app 2.15.17
netlify-cms-core 2.40.11
netlify-cms 2.10.137```
- Git provider: Github
- OS: macOS 11
- Browser version Firefox 89

- Node.JS version:

**CMS configuration**

⁄https://github.com/jasikpark/jasik-xyz/blob/main/static/admin/config.yml

**Additional context**

This could be related to using the page bundles feature w/ Hugo since I'm getting several weird bits with it.

Browser console.log

netlify-cms-app 2.15.17 index.js:25:12

netlify-cms-core 2.40.11 bootstrap.js:83:12

netlify-cms 2.10.137 index.js:27:12

 Checking for Unpublished entries API.js:765:12

TypeError: o is undefined

    previewUrlFormatter formatters.js:187

    getDeploy backend.js:954

    loadDeployPreview deploys.js:84

    Redux 2

    loadDeployPreview Editor.js:410

    componentDidMount EditorToolbar.js:441

    React 2

    unstable_runWithPriority scheduler.production.min.js:19

    React 4

    unstable_runWithPriority scheduler.production.min.js:19

    React 4

    Redux 7

    retrieveLocalBackup entries.js:604

    Redux 2

    componentDidMount Editor.js:239

    React 2

    unstable_runWithPriority scheduler.production.min.js:19

    React 4

    unstable_runWithPriority scheduler.production.min.js:19

    React 4

    Redux 7

    loginUser auth.js:110

    promise callback*t.loginUser/< auth.js:105

    Redux 2

    handleLogin App.js:153

    componentDidMount AuthenticationPage.js:161

    React 2

    unstable_runWithPriority scheduler.production.min.js:19

    React 4

    unstable_runWithPriority scheduler.production.min.js:19

    React 4

    Redux 7

    loadConfig config.js:574

    r Redux

    _ bootstrap.js:116

     index.js:10

    Webpack 5

react_devtools_backend.js:2560:23

TypeError: o is undefined

    previewUrlFormatter formatters.js:187

    getDeploy backend.js:954

    loadDeployPreview deploys.js:84

    Redux 2

    loadDeployPreview Editor.js:410

    componentDidMount EditorToolbar.js:441

    React 2

    unstable_runWithPriority scheduler.production.min.js:19

    React 4

    unstable_runWithPriority scheduler.production.min.js:19

    React 4

    Redux 7

    k editorialWorkflow.js:308

    r Redux

    loadEntry withWorkflow.js:66

    componentDidMount Editor.js:244

    React 2

    unstable_runWithPriority scheduler.production.min.js:19

    React 4

    unstable_runWithPriority scheduler.production.min.js:19

    React 4

    Redux 7

    loginUser auth.js:110

    promise callback*t.loginUser/< auth.js:105

    Redux 2

    handleLogin App.js:153

    componentDidMount AuthenticationPage.js:161

    React 2

    unstable_runWithPriority scheduler.production.min.js:19

    React 4

    unstable_runWithPriority scheduler.production.min.js:19

    React 4

    Redux 7

    loadConfig config.js:574

    r Redux

    _ bootstrap.js:116

     index.js:10

    Webpack 5

react_devtools_backend.js:2560:23