Unable to save changes to the event documents

Tjeerd reported below issue
1. Log-in to CMS (hosting) with admin user-id
2. Navigate to Documents >> nl >> events >> 2010 >> 01 >> cms-in-de-overhied
3. Click on edit button
4. Go to Introduction field, at the last sentence just replace the . by !
5. Click on Save & close

Issue - I noticed that ! is replaced by .
Next time he typed some text than clicked on save & close. Still the changes were not saved.
Expected - The changes should be saved
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I tried the same steps on my machine, it worked fine.
I tried the same steps on a local go green build (3.01.08-snapshot) it worked fine
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So I scanned the cms logs of both the production nodes, below is my understanding
1. There is no logs for the documents opened/closed "/events/"
2. Lots of error regarding the changes in sitemap items for NL
3. Some error related to session management
4. And off-course there are lot of errors which are not related in this case

So this issue is cascading effect of the changes done for sitemap configuration of NL and the event document Tjeerd was trying to edit was not actually in edit mode.

In my opinion this is serious bug which need through investigation, even if it occurs once in a while.