Hi! After some faffing about with tags on MusicBee, I think MusicBee handles multiple artists not to spec. According to the
id3 v2.3.0 specification, in a TPE1 frame, the artists should be seperated by a slash (0x2F). However, when adding multiple artists through the metadata editor, an empty byte (0x00) is added as a separator instead.
Expected output: Artist 1[2F]Artist 2

MusicBee output: Artist 1[00]Artist 2

For reference, this is what the tagging screen looks like:
