This small test case hopefully helps to track down the bug:

react-dom.development.js:86 Warning: Internal React error: Expected static flag was missing. Please notify the React team.

It only appears if I render the component with a timeout as well as when I'm using Jss. It could have something to do with the new concurrency model in React (at least that would make sense to me).

How to start:

• clone the repo
• run yarn
• run yarn run dev

The div is rendered after 1 second. This is when the exception comes up