I have produced a sample for this rare bug (http://www.hydrogenaudio.org/forums/index.php?showtopic=62163) I keep experiencing on foobar2000 on VBR mp3s that uses very low bitrate frames (~112kbps).
The sample is a desktop recorded sound of me using foobar and playing some tracks that have silence at the begaining that uses low bitrates frames, anyway halfway through the sample the bug seems to disappear.
Also am very sorry about the sound of this sample, since I used the Sound Recorder app, that comes with Windows and its default settings are a complete joke, but the glitches on the sample sounds the same though.