UserAgent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.103 Safari/537.36

Steps to reproduce the problem:
var url = "http://virtualoffice.servcorp.co.jp/index.html"
var differentPath = "./differentPath.html"

    chrome.downloads.download({
      url: url,
      conflictAction: "uniquify",
      filename: differentPath
    })

What is the expected behavior?
The file name should change.

What went wrong?
The filename remains as the original filename.

WebStore page: 

Did this work before? Yes About 2 months ago

Chrome version: 51.0.2704.103  Channel: n/a
OS Version: 6.1 (Windows 7, Windows Server 2008 R2)
Flash Version: Shockwave Flash 22.0 r0