Here's a screenshot of the two editors problem I get.
Here's browser version info.
It is sometimes accompanied by this error in the console, but not always. It may not be related.
I've seen a couple comments over on the WordPress forums about this. Let me know if I can do anything to help with testing.
I'm working on a fix for this right now!
Has the latest github code fixed this issue for you?
@elliotcondon It looks like it's fixed. Also, the error in the console I mentioned is coming from another plugin.