Yeah ... in those cases the audio file is deliberately corrupted. The bitrate does not match what it should be for the file size & length of song. These will be more difficult to recognise in the new LW 5 & FW 5 due to the way they are displayed.

I suspect the LW devs have dug a hole for themselves by leaving out various functions that were in the program from the beginning, or at least since version 2.