Why is my music split up on my iphone?

Ever since updating to iOS 6 the music on my phone is randomly split up, sometimes by artist, sometimes by album. I'm using an iPhone 4s and iTunes match.

I know this is isn't a metadata thing because it was never a problem before and I've updated all the tags to make sure.

With one artist in particular, it started out with just a single song. So I would browse to the artist and see two entries. One entry was all of the albums from that artist, and the other was just a single song. Then a few days later it was showing an entire album under this second artist entry. Now it is about half the music from this artist. For others it is within an album, so there will be a few songs from a particular album listed separat

Again, I know it isn't the metadata, and this didn't start until I updated to iOS 6.