It seems to be a caching issue, though there isn't a single cause for it. There is still ongoing discussion, as well as multiple suggestions for fixes about this on the Wordpress issue tracker:
You can fix the symptoms by ensuring pages under "/wp-admin" are never cached. If using Apache, you can do this by adding the following to your Apache configuration:
Header unset ETag
Header set Cache-Control "max-age=0, no-cache, no-store, must-revalidate"
Header set Pragma "no-cache"
Header set Expires "Wed, 11 Jan 1984 05:00:00 GMT"
You should place this after any other
Header directive in your Apache configuration. If ensure you can put this in either:
.htaccess on your project root;
<VirtualHost> section of your main Apache configuration (assuming you're using virtual hosts!)
And then check in a web browsers these headers come as expected.
For a solution fixing the issue (rather than just the symptoms) keep following the bug report above.