Garbled characters when downloading Japanese name file from media library

hello.

when downloading the file (.pdf) saved in the media library from the page, it garbled when the file name is Japanese. The version of kentico is v11.0.1

Next is the target header information.

Accept-Ranges: bytes
Cache-Control: private, must-revalidate
Content-Disposition: inline; filename="openid認証について.pdf"
Content-Length: 1164024
Content-Type: application/pdf
Date: Thu, 11 Oct 2018 06:37:38 GMT
Server: Microsoft-IIS/10.0
X-AspNet-Version: 4.0.30319
X-Frame-Options: SAMEORIGIN
X-Powered-By: ASP.NET

filename="openid認証について.pdf" is Garbled characters