I'm a bit of a fan of English Indie music. I uploaded my White Lies CD To Lose My Life to IML. The first four songs have been replaced by a hip hop duo called Da Muzicianz. (Needless to say i do not own any of their stuff).
Some tracks on Abba's Gold Greatest Hits album have been replaced with Euro Disco Tributes to the songs!
As others have said 95% of live music has been replaced with Studio versions. And some studio songs replaced with live versions.
Hundreds of examples of artwork wrong.
IML does not work very well.
My best one yet has been between two albums of the same artist. Both have the same song but way different versions. Song from album A got replaced with the song from album B, song from album B got replaced with song from album A. I just facepalmed and sighed.