Recently Google introduced a new feature to Google Music. Instead of having to manually upload your songs to the service Google will scan and automatically match the tracks in Google Play. For the first 20.000 tracks this service is free. However some songs might be incrrectly matched.
If you have that kind of problem simply click on the arrow to the right of the title and choose "Fix Incorrect Match" from the dropdown menu. Now you can upload your own version.
The fix works only for individual songs, at least for now. There doesn't seem to be an option for entire albums.