Jitter introduced in MP3 files (64 kbps, 2 channel, 22 kHz sample rate) after Audio Import

I've uploaded many MP3 files of the same type (64 kbps, 2 channel, 22 kHz sample rate) via Audio Import, yet when I use the Audio module to either playback in browser or download, the resulting file has a jitter introduced every second or so.

Before file: http://isss.org/media/BEFORE-20070807_ISSS_1100_HardSoftEastWest_Kijima_...
After file: http://isss.org/media/AFTER-20070807_ISSS_1100_HardSoftEastWest_Kijima_N...