ID3v2.3
does not support slash characters in artist names. According to the specification, your tag indicates two artists, named "AC" and "DC".
From
http://www.id3.org/id3v2.3.0.txt :
QUOTE
TPE1
The 'Lead artist(s)/Lead performer(s)/Soloist(s)/Performing group' is used for the main artist(s). They are seperated with the "/" character.
While I agree that this is braindead, this behavior complies with the specification. If you don't like it, use ID3v2.4 instead.