The default Brasero application, as far as I can tell, does nothing at all when asked to burn lots of mp3 tracks to more than one CDR. I know about the permission issues with some of its supporting applications (cdrdao etc), and fixing those does not overcome the fundamental problem I'm seeing that the "Burn Multiple Disks" option does precisely nothing at all.
Is that just a known problem (like the permissions problem with the underlying tools)? I realize that not too many people burn old-school audio CDs nowadays.
Sorry this is 16.04, I apologize for not clarifying.
Audio "projects" involving mp3 file groups that do fit on a single plain audio CD can be burned successfully with Brasero.