Custom theme breaks on 4.0.0-alpha.7

[pheuter]

Expected Behavior 🤔

Custom theme should load fine as it did before on 4.0.0-alpha.6:

const theme = createMuiTheme({...});

return (
  <StylesProvider generateClassName={generateClassName}>
    <ThemeProvider theme={theme}>
      <CssBaseline />
      <div>
        <Nav />
        <main>{this.props.children}</main>
      </div>
    </ThemeProvider>
  </StylesProvider>
);

Current Behavior 😯

SSR styles appear broken, and when the client-app loads all components change to the default material-ui theme.

Steps to Reproduce 🕹

Context 🔦

I'm suspecting this may have something to do with memoizing the theme in the latest update, but not sure.

Your Environment 🌎

• material-ui/[core|styles] - v4.0.0-alpha.7
• react - v16.8.6
• jss - v10.0.0-alpha.16

[oliviertassinari]

@pheuter Duplicate of #15264?

[pheuter]

@oliviertassinari Could be, I'll close this issue for now until some new information comes up, thanks.