M4A tracks don't have an artist
I have the same issue here.
Any applications that use the system media library (which include DoubleTwist, Winamp, PowerAMP) don't display the artists.
I downloaded a tag editor app onto the phone, but when I go to edit the tags, they are all correct, it does seem to be an issue with the system, and not any apps.
Has anyone tried installing the default music player from vanilla Gingerbread?
Or is the media library part of the OS more than just that app?