TYPO3 Core

The method for getting the BackendUsers via the \TYPO3\CMS\Workspaces\Service\StagesService does not provide the 'lang' of a BackendUser.
This is problematic when reaching the notifyStageChange method of the \TYPO3\CMS\Version\Hook\DataHandlerHook, because the recipients could be given to this method via the $notificationAlternativeRecipients parameter and thus won't be processed by getEmailsForStageChangeNotification but simply be copied to $emails which later defines the language of the E-Mail template for the recipients. The result will be E-Mails that does not have the same language as the BackendUser selected for his account.
This is only affecting workspaces mainly through the \TYPO3\CMS\Workspaces\ExtDirect\ActionHandler class and the backtraces are extremly complicated.

The method \TYPO3\CMS\Workspaces\ExtDirect\ActionHandler->getRecipientList also needs the 'uc' attribute of the BackendUser, which is not provided as far as I can see.

All this would be fixed by simply adding `lang, uc` to the field select list of the getBackendUsers method of \TYPO3\CMS\Workspaces\Service\StagesService