Undeletion will not be performed if it will result in the top page or file revision being partially deleted. In such cases, you must uncheck or unhide the newest deleted revision.
MediaWiki:Undeleterevdel
From Monica Ioana Pop Silaghi website
Undeletion will not be performed if it will result in the top page or file revision being partially deleted. In such cases, you must uncheck or unhide the newest deleted revision.
