Multiple users have started reporting they're unable to create new posts or pages.

@samouri could this be React 16-related?
could this be React 16-related?
The upgrade's been merged some 20 hours ago, so I think we would've seen this earlier if it was related...
This bug is only visible in production and not stage.
This was "fixed" by merging #20286 . One possible explanation may have been bundling hash collisions with post-editor.css.
Noting an earlier report that came in through the forums at Nov 30, 2017, 12:01 PM UTC: https://en.forums.wordpress.com/topic/updating-posts-leads-to-blank-page?replies=21
There were 40-50 users who tweeted us about this issue as well.
Several of the Twitter users mentioned above have since confirmed that it's fixed for them.
@KokkieH, thank you for the follow-up!
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Several of the Twitter users mentioned above have since confirmed that it's fixed for them.