song a - album art a
song b - album art b
song c - no art

these songs r AAC, for MP3 it's ok.
When you import this song c will have the art from song b.

h4. Additional Information
This is still happening for me.
Some facts:
.In the database the id for the album is 1 which is Unkown
.There is no thumbfile created related to the song (artis or anything)

logs from a sample scan
Scan from song with albumart:
25-3-2006 10:57:51 mp4 tag: scan D:\Media\Music\Boris\Rely on Me\When You Think Of Me.m4a
25-3-2006 10:57:51 create 128x128 thumbnail ->thumbs\music\albums\Boris-Rely on Me.jpg
25-3-2006 10:57:51 create 512x512 thumbnail ->thumbs\music\albums\Boris-Rely on MeL.jpg

Scan on song with no album art wich will get the album art from Boris (previous m4a)
25-3-2006 10:57:53 mp4 tag: scan D:\Media\Music\C.B. Milton\Onbekend album\Real Love.m4a
25-3-2006 10:57:53 create 128x128 thumbnail ->thumbs\music\albums\Captain Hollywood Project-Love Is Not Sex.jpg
25-3-2006 10:57:53 create 512x512 thumbnail ->thumbs\music\albums\Captain Hollywood Project-Love Is Not SexL.jpg

The captain hollywood thumbs r from the next mp3 so that fine.
Hope this helps.