TYPO3 Core

This is a bug in extension workspaces.

In the meantime, you should change file Classes/Service/Stages.php around lines 125-140 to read:

if ($workspaceRec['custom_stages'] > 0) {
    // Get all stage records for this workspace
    $workspaceStageRecs = $GLOBALS['TYPO3_DB']->exec_SELECTgetRows(
        '*',
        self::TABLE_STAGE,
        'parentid=' . $this->getWorkspaceId() . ' AND parenttable=' . $GLOBALS['TYPO3_DB']->fullQuoteStr('sys_workspace', self::TABLE_STAGE) . ' AND deleted = 0',
        '',
        'sorting',
        '',
        'uid'
    );
    foreach($workspaceStageRecs as $stage) {
        $stage['title'] =  $GLOBALS['LANG']->sL($this->pathToLocallang . ':actionSendToStage') . ' "' . $stage['title'] . '"'; 
        $stages[] = $stage;
    }
}

Problem will be tackled with with related issue, in extension workspaces.