FileIterator.next() not working

07/19/2017 The FileIterator.next() method has ceased to work.

Message: The following object can not be obtained: iterator has reached the end of the set.

Search for a file created before 07/19/2017 is correct.

All scripts worked correctly for a long time until 07/19/2017, perhaps that has changed in the methods of GAS.

Where can I go for help?

Code sample

var file = DriveApp.getFilesByName('FileName').next().getId();

and

var files = DriveApp.getFilesByName('Filename');  
if (files.hasNext()) {

    SpreadsheetApp.openById(files.next().getId()).getSheets()[0].appendRow([new Date(), Family, Name]);  
} 

and

var firstLevelFolderName = "MyFolderName";
var folders = DriveApp.getFoldersByName(firstLevelFolderName);
var firstLevelFolder = (folders.hasNext()) ? folders.next() : DriveApp.createFolder(firstLevelFolderName);