Error thrown when attempting to use Material UI StylesProvider

[colebillys19]

Repo: https://github.com/colebillys19/simple-storybook
By default, Material UI styles get applied after all other styles. In order to inject them first, their docs instruct to wrap your component tree in a StylesProvider and pass it the injectFirst prop. After doing this and starting up the storybook I get the following error:

Invariant Violation: Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: undefined. You likely forgot to export your component from the file it's defined in, or you might have mixed up default and named imports.

Check the render method of `storyFn`.
    at http://localhost:9009/vendors~main.dde01deb994fa36497d0.bundle.js:130394:34
    at createFiberFromTypeAndProps (http://localhost:9009/vendors~main.dde01deb994fa36497d0.bundle.js:130397:13)
    at createFiberFromElement (http://localhost:9009/vendors~main.dde01deb994fa36497d0.bundle.js:130418:15)
    at reconcileSingleElement (http://localhost:9009/vendors~main.dde01deb994fa36497d0.bundle.js:120888:23)
    at reconcileChildFibers (http://localhost:9009/vendors~main.dde01deb994fa36497d0.bundle.js:120945:35)
    at reconcileChildren (http://localhost:9009/vendors~main.dde01deb994fa36497d0.bundle.js:123049:28)
    at mountIndeterminateComponent (http://localhost:9009/vendors~main.dde01deb994fa36497d0.bundle.js:123756:5)
    at beginWork$1 (http://localhost:9009/vendors~main.dde01deb994fa36497d0.bundle.js:124844:16)
    at HTMLUnknownElement.callCallback (http://localhost:9009/vendors~main.dde01deb994fa36497d0.bundle.js:106705:14)
    at Object.invokeGuardedCallbackDev (http://localhost:9009/vendors~main.dde01deb994fa36497d0.bundle.js:106755:16)

Take a look at .storybook/config.js - I have working code (that doesn't include StylesProvider) included.

Expected behavior
No error should be thrown.

Screenshots

System:

Environment Info:

  System:
    OS: macOS Mojave 10.14.6
    CPU: (4) x64 Intel(R) Core(TM) i5-7360U CPU @ 2.30GHz
  Binaries:
    Node: 12.12.0 - /usr/local/bin/node
    Yarn: 1.19.1 - /usr/local/bin/yarn
    npm: 6.11.3 - /usr/local/bin/npm
  Browsers:
    Chrome: 78.0.3904.70
    Safari: 12.1.2
  npmPackages:
    @storybook/addon-a11y: 5.2.1 => 5.2.1 
    @storybook/addon-actions: 5.2.1 => 5.2.1 
    @storybook/addon-backgrounds: 5.2.3 => 5.2.3 
    @storybook/addon-docs: 5.2.4 => 5.2.4 
    @storybook/addon-knobs: 5.2.1 => 5.2.1 
    @storybook/addon-storyshots: 5.2.3 => 5.2.3 
    @storybook/addon-storysource: 5.2.1 => 5.2.1 
    @storybook/addons: 5.2.1 => 5.2.1 
    @storybook/react: 5.2.1 => 5.2.1 
    @storybook/source-loader: 5.2.4 => 5.2.4 

[shilman]

@colebillys19 I'm not seeing any error when I download & run the repo?