Exporting to PDF with inlined image which name contains umlaute, breaks Confluence

Trying to export a page contains an image, where the image's name contains umlaute character, breaks Confluence. The steps to reproduce:

1. Create an image file or rename the existing image file with the text aerisä.gif. (I have tried to reproduce using image typed: gif, png, jpg).
2. Upload the image to a page.
3. Put the image to the page using the following wiki markup:

   !aerisä.gif!
   

4. Export the page to PDF.