Log entry I cannot explain

[simoncn]

This message is telling you that this file:

András Schiff/Franz Schubert_ Sonatas & Impromptus/01 4 Impromptus, Op. 90, D. 899_ 1. Allegro molto moderato.flac

has an ALBUM_ARTISTS tag 'András Schiff' with a sort value 'Schiff, András' applied by an ALBUM_ARTISTS_SORT tag in this file. Some other file in your library that was scanned previously has an ALBUM_ARTISTS tag 'András Schiff' with a sort value 'Shiokawa, Yuuko'. It isn't possible for the ALBUM_ARTISTS tag value 'András Schiff' to have two different sort values applied by the tags in diiferent files in your library.

In this case it appears that the tagging of the file

András Schiff/Franz Schubert_ Sonatas & Impromptus/01 4 Impromptus, Op. 90, D. 899_ 1. Allegro molto moderato.flac

is correct and it is the other file that has an incorrect value for ALBUM_ARTISTS_SORT.