TYPO3 Core

I've got several projects already running on TYPO3 6.2beta (still under development). Since beta1 I'm experiencing an annoying problem. As soon as you install a "problematic" extension the new extension manager throws some kind of exception/ PHP error (always something different - I'll try to gather more information when the problem occurs again). When this happens the PackageStates.php is cleaned and looks like the following snippet:

<?php
# PackageStates.php

# This file is maintained by Flow's package management. Although you can edit it
# manually, you should rather use the command line commands for maintaining packages.
# You'll find detailed information about the typo3.flow:package:* commands in their
# respective help screens.

# This file will be regenerated automatically if it doesn't exist. Deleting this file
# should, however, never become necessary if you use the package commands.

return array (
  'packages' => 
  array (
  'version' => 4,
)
 ?>

Yesterday this happened to me again. I've got a fresh CMS 6.2beta4 and tried to install the current extension_builder extension.