Which file format? Which external applications do you use?
This is probably not an issue of Mixxx, but of a 3rd party application that doesn't handle multiple COMM frames with different descriptions (MP3/ID3v2) correctly.
Similar issue for Ogg/FLAC files with COMMENT (recommended) vs. DESCRIPTION (legacy) fields.
Which file format? Which external applications do you use?
This is probably not an issue of Mixxx, but of a 3rd party application that doesn't handle multiple COMM frames with different descriptions (MP3/ID3v2) correctly.
Similar issue for Ogg/FLAC files with COMMENT (recommended) vs. DESCRIPTION (legacy) fields.