If your music file and directory naming is not exactly to Plex’s liking all kinds of weird stuff can happen. This seems especially true with Various Artists. I have seen VA albums under the name of another artist that I know doesn’t even exist in my VA content.
If you are following the official naming guidelines and it is still screwed up, I would try the “Plex Dance” – remove the content, re-scan, then add it back and scan again.
If it’s still screwed up … 
