Thank you for your bug report and the sample files!
I've tested your sample file (02 BEFORE.mp3) on Fedora 24 x86-64 with Mixxx 2.1.0-pre-alpha. The file is decoded completely without any errors, please see the attached screenshot with the waveform showing the end of the file where the audio fades out around 2:50.
Unfortunately I'm not able to perform any tests on OS X. Mixxx on OS X uses the Apple Core Audio framework for decoding MP3 files instead of MAD on Linux.
Thank you for your bug report and the sample files!
I've tested your sample file (02 BEFORE.mp3) on Fedora 24 x86-64 with Mixxx 2.1.0-pre-alpha. The file is decoded completely without any errors, please see the attached screenshot with the waveform showing the end of the file where the audio fades out around 2:50.
Unfortunately I'm not able to perform any tests on OS X. Mixxx on OS X uses the Apple Core Audio framework for decoding MP3 files instead of MAD on Linux.