Any idea how to make Google Chrome render a PDF when it's URL contains non-utf8 and non-ascii (but url-encoded) chars?

Question

Google Chrome seems to have Problems in rendering a PDF file, if the URL to that file contains non-ascii and non-utf8 url-encoded chars.

This is reproducible in a very simple way:

1. Take any http-url to a PDF file.
2. Just add the url-parameter string '?a=%F6' to the given url ('%F6' is the url-encoded value of the german umlaut 'ö' in win-1252 codepage)

Chrome will not render the PDF file.

If you add an utf8 string that is url-endcoded it'll work: e.g: '?a=%C3%B6'

This is confirmed with newest Google Chrome and Chromium (45.0) versions on Windows and Linux.

I read this blog, but didn't find a hint that non-utf8 encodings wouldn't work.

If i disable the 'PDF viewer Plugin' (in about:plugins) then the PDF is getting downloaded at least.

Any ideas about this?