I'm using the new PageManager which is a really valuable, cool extension for Sitecake - thanks for that!
I have found a little issue (maybe appears only on IIS and PHP 5.6.30):
1. I open PageManager.
2. I click on an existing page and then on Duplicate. The new page appears.
3. I click on the blue "Publish" button. My new page disappears.
4. I close the PageManager and reopen it again - my new page is correctly listed.
In my opinion the problem is that the reload (async ajax?) of the PageManager is to fast after the click on the Publish button and the filesystem is not finished with creating the new file.
Its not a big deal for me to use this workaround with repopen PageManager, but maybe its possible to easy fix that in a future version.