Here we have isolated the confusion in these terms:

$ egrep 'tooltip-(roll|undo)|editundo|^.rollback_short' MessagesEn.php *Zh*.php|sort -t: -k 2
MessagesEn.php:'editundo'                => 'undo',
MessagesZh_hant.php:'editundo'                => '撤銷',
MessagesZh_tw.php:'editundo'                => '撤銷',
MessagesZh_hans.php:'editundo'                => '撤销',
MessagesEn.php:'rollback_short'   => 'Rollback',
MessagesZh_tw.php:'rollback_short'   => '復原',
MessagesZh_hans.php:'rollback_short'   => '恢复',
MessagesZh_hant.php:'rollback_short'   => '恢復',
MessagesEn.php:'tooltip-rollback'                => '"Rollback" reverts edit(s) to this page of the last contributor in one click',
MessagesZh_hans.php:'tooltip-rollback'                => '‘反转’可以一按恢复上一位贡献者对这个页面的编辑',
MessagesZh_hant.php:'tooltip-rollback'                => '『反轉』可以一按恢復上一位貢獻者對這個頁面的編輯',
MessagesEn.php:'tooltip-undo'                    => '"Undo" reverts this edit and opens the edit form in preview mode. 
MessagesZh_hans.php:'tooltip-undo'                    => '‘复原’可以在编辑方式上开启编辑表格以便复原。它容许在摘要中加入原因。',
MessagesZh_hant.php:'tooltip-undo'                    => '『復原』可以在編輯模式上開啟編輯表格以便復原。它容許在摘要中加入原因。',

As how to resolve the confusion, I leave that up to the real Chinese.