Steps to repeat:
Add files with a 'ß' to an object. Create a mets.xml file.
The images cannot be viewed in the dfg viewer as forwarding by the MCRDFGLinkServlet fails with
Image "your file name here" not found in the MCRDerivate. Please contact an administrator.
Fehlercode: 409 [Conflict]
example from production: https://archive.thulb.uni-jena.de/ufb/servlets/MCRDFGLinkServlet?deriv=ufb_derivate_00010754