No file format, wrong filenames in study documents

Summary

Study Document files get downloaded with weird names and without a file extension.

Steps to Reproduce

Click on a filename in Study Documents to download it

File gets downloaded and saved with a weird name (e.g. 5e838793a4c2f7593cf01321) and can not be opened until a .pdf file extension is manually added. This happens with all pdfs but not with .zip files.

Additional Debug Information

OSX Catalina 10.15.6, Firefox 81.0 (64 Bit)