While going through my history and saved lists I found many instances where song have multiple ids associated even if they are from the same album and artist. For example:
7oK9VyNzrYvRFo7nQEYkWN Mr. Brightside Hot Fuss 003vvx7Niy0yvhvHt4a68B Mr. Brightside Hot Fuss 0eGsygTp906u18L0Oimnem Mr. Brightside Hot Fuss
In track information the markets sometimes are different and even the popularity but it is basic the same song.
This makes parsing for listening history statistics more problematic that it should be. Also trying to make an app for dynamic playlists comparing saved tracks with history and cleaning my saved tracks to avoid duplication is unnecessary time consuming.