Sorry to post another possible bug, but I am doing quite a bit of work on tagging, which I hope will ultimately be helpful.
When writing out static tags to FLAC, if there is no Artist then Composer gets written out as Artist as well as Composer. I think the correct treatment should be to write out a blank artist.
I appreciate that within Muso classical composers can be treated as artists, but I think the tags should be maintained separately. Sometimes the (performing) artist can be the composer (even in classical music) and sometimes not, so it is impossible to decipher what was intended by looking at the tags that were written.
Composer tag writing
Re: Composer tag writing
You're right, I did that for selfish reasons since my squeezebox players are configured to show "artist - track" and I like it to show composer for classical rather than nothing. I'll put it on a personal switch 
Re: Composer tag writing
The Mp3tag action I am writing will also put composer into Artist for display on the SB touch/ ipeng if there is no artist. Otherwise it displays "Artist (instrument)". A separate MAINPERFORMER tag is kept to track the real artist name. The action is designed to keep the FLAC tags and the Muso fields in step, but optimised for their different uses, simply by running the action after any FLAC tag modification. This means that the tags can be maintained in Muso (more user-friendly, generally) and exported. Running the action then gives you the optimised display for LMS. Similarly if you amend the underlying FLAC tags, these can be imported into Muso and interpreted correctly provided you run the action first. Almost done - will write it up and announce when finished.
Re: Composer tag writing
Done in 2.3.02