調べてみましたが、「子ページの設定」画面 => $cList = $ct->getPages()を呼び出す(\concrete\elements\block_master_collection_alias.php 10行)=> function getPages()を呼び出す(\concrete\models\collection_types.php 232行)
getPages()の中
$r = $db->query("select Pages.cID, Collections.cDateAdded, Collections.cDateModified, max(cvID) as cvID, cvName from Pages inner join Collections on Collections.cID = Pages.cID inner join CollectionVersions on Pages.cID = CollectionVersions.cID where ctID = ? and cIsTemplate = 0 group by CollectionVersions.cID order by cvName asc;", array($this->getCollectionTypeID()));
このsqlの書き方が問題発生の原因と思われます。
一番手っ取り早くて簡単と思われる解決方法は、sqlを書き換えることです。
$r = $db->query("select Pages.cID, Collections.cDateAdded, Collections.cDateModified, max(cvID) as cvID, cvName from Pages inner join Collections on Collections.cID = Pages.cID inner join (select * from CollectionVersions order by cvID desc) as Foo on Pages.cID = Foo.cID where ctID = ? and cIsTemplate = 0 group by Foo.cID order by cvName asc;", array($this->getCollectionTypeID()));