Sounds odd. Michael, can you provide exact steps to allow us to try to reproduce this effect? I can see roughly what to do but would like to see steps for two admins to try.
You also mention 3.1.1. I assume this is an svn version, which revision?
Where do I find the exact version? I got the tarball ezpublish-3.1-1.tar.gz dated July,5.
The steps to reproduce the failure: One administrator (e.g. the one in Munich) navigates to "Set up/class groups/content". Then edit an object, say "article". At the same time, another administrator (e.g. the one in Hamburg) has opened the same object ('article'). Neither of them knows, that the object is being viewed by another admin. The both leave the object by pressing 'Discard' at the same time ....
Then the object ('article') has disappeared, the page is destroyed. Because my first idea, bringing back that object via ezcontentclass-table failed, the object (article) is still listed in that table.
There must be one little flag elsewhere, that tells ez that the object isn't valid anymore.