TYPO3 Core

Clearing all caches with rm -rf typo3temp/Cache/* and trying to install the form sysext afterwards gives the following error

Fatal error: Class 'TYPO3\CMS\Form\Utility\FormUtility' not found in /.../typo3/sysext/form/ext_localconf.php on line 5

1. Go to the extension manager and uninstall the form extension, leave the window as it is. (It shows only the form extension in the filtered extension list and the icon in front would install the ext again.)
2. rm -rf typo3temp/Cache/*
3. Click on the install-button now in the BE windows
4. You'll get the error from above
5. Click on the Extension Manager in the module frame to reload the module. (The extension list appears still filtered and form shows up as installed again.)

Don't know if it is an autoloading issue, but looks like the class loader is not up to date at this point in time.