Behavior: Blue download buttons for each track do not work at all, and downloading selected tracks causes an error page and logs the user out. This then results in tracks moving off the Downloads page.
Workaround: This is caused by custom file naming. The current workaround is to use at least one key word and to use the curly brackets around them like {track_name}_({mix_name}) and NOT track_name(mix_name).
Account Settings > Download Preferences