TYPO3 Core

Sounds fishy. Bootstrap first loads LocalConfiguration, then loads AdditionalConfiguration. With your db settings in AdditionalConfiguration, there shouldn't be an issue "db call fired to wrong target" then.

Are you using EXT:environment?

No, i don't use EXT:environment.

In general I think it's a really small and simple setup. As extensions I only use the following:
- femanager
- fluidcontent
- fluidpages
- flux
- powermail
- realurl
- sourceopt
- vhs

In addition to them I have installed 2 own written extensions but they are only normal FE-extensions.

I already tested exactly the same project on another webserver with PHP 5.6 installed - all works fine!

If you need more informations about the server setup or anything else please give me some feedback.

Are you sure your settings are loaded?

If you switch PHP version and/or server environment and the application doesn't work anymore the first thing I would check if there are no PHP errors etc.

Your error logging is set to E_ALL and the error log is empty?

Yes, i am sure.
The install tool shows me the correct DB credentials. The normal TYPO3 page rendering seems to connects to the correct database but if i call the page via an AJAX HTTP Request (configured with pagetype which bootstraps an extension) the AdditionalConfiguration isn't loaded/used.
The PHP error log is empty, maybe I have a absolutely weird setup but I don't think so. Currently I solved the problem by changing the LocalConfiguration.php at the Deployment process. This isn't a nice solution but at the moment I have no other idea how to handle that.
BTW: The Install-Tool and the TYPO3 BE shows me the correct Application Context.

Hi Thomas,
Can you provide a minimal setup to reproduce the issue?
I did some tests but couldn't reproduce the issue you mention.
Without steps to reproduce we will not be able to fix the issue unfortunately.
Thanks