I bought a new album with my iPad. I later went to listen to the same album on my desktop Mac Mini. I searched for the album and couldn't find it. I went into purchases and could see it there, but it didn't show up in my Album, Song, or Artist list. I went to the iTunes store and looked under the purchased area, and could see the album, and it showed that it had already been downloaded on the computer.
I tried all sorts of things, but eventually, I just turned off iTunes Match. It became visible. I then turned Match back on, and it was still visible.
I've had this happen twice now on two different computers.
Mac mini, OS X Mountain Lion (10.8.2), 2.4 Ghz Intel Core2 Duo, 8 GB RAM