Regression - Internal link to document with unicode name does not work

1) login (gogreen, admin/admin)
2) Edit a document )/content/documents/hippogogreen/events/2014/11/bio-and-eco-expo-2014) and type/select some text in the description
3) Click internal link and link to /content/documents/河马转到绿/常問問題/為什麼回收不是強制性的
4) Save & Close
5) Click the internal ink
Expected: Linked document is opened
Actual: Document is not opened

Observation: When the linked document is renamed to a ascii name and the document containing the linked is saved again, the link works again.