EDIT: After further investigation, it looks like the duplicate values actually show up in MC. They are divided by a "/".
Which is why I was hopping from thread to thread, because the image that hints at that is over in your other thread:
https://yabb.jriver.com/interact/index.php/topic,114615.msg793123.html#msg793123I still can't replicate the problem. Maybe because I am only using MC. I converted a track to AIFF and all its tags were correct. It was initially tagged with multiple Artists and an Album Artist, and they carried across correctly.
So I edited the [Album Artist] tag in MC, and that still all worked correctly. I checked the Tag Dump area and no extra tags showed.
I'm wondering if there are multiple tags in the file itself, and MC is combining those tags and putting them into its equivalent. i.e. Some files seem to have an "Album Artist" tag and an "AlbumArtist" tag. Maybe MC is just reading those and putting them both into [Album Artist]? Actually, maybe not. I just checked a number of FLAC files ripped directly from CD, and they have both the "Album Artist" tag and an "AlbumArtist" tag stored in the file, as viewed using MC's Tag Dump feature. Converting them to AIFF doesn't create the problem.
MC then writes other tags like Dynamic Range, Tempo, Replay Gain, etc. I can see those tags in the tag editor. The files that have those tags (Dynamic Range, Tempo, Replay Gain, etc.) do also have another value in [Album Artist] which I did never add manually.
Those tags are the result of MC doing Audio Analysis. So I deleted all those tags from the AIFF track I created by converting an M4A file and ran Audio Analysis on it. Tags are still correct.
So I converted three more FLAC files to AIFF, saving them to a completely separate new directory that isn't watched by MC. Then I imported that directory manually. All imported correctly with no extra tags.
I'm still thinking that a third party application is involved in this somehow. Or perhaps the original source of the digital tracks. But if they were ripped from CD using dBpoweramp, and that was the only processing before importing into MC, then dBpoweramp has to be the source of the extra data as ripped CD files contain no tags until the ripping software adds them.
Was there something special about the files you tested with RD? I used files directly ripped from CD using MC for the FLACs, and the M4A was just converted from a FLAC version.
BTW, I could understand MC converting an "Album Artist" tag of "Artist; Artist" to "Artist/Artist" during import, as ";" is a separator and MC might be programmed to replace the separator in a non-list field. So I changed the [Album Artist] tag in a FLAC file to "Artist; Artist", which it saved as exactly that, then converted it to AIFF into that independent directory, then manually imported it. Still no joy. The [Album Artist] tag in the AIFF files came in as "Artist; Artist".
If either of you can provide a way I can reproduce the problem using MC only, I will try. That would at least confirm a MC issue.
Maybe it would be better to address the reason you are tagging with dBpoweramp. From the other thread:
I do not use MC for tagging because of the issues I describe in the other thread. Also I never got to find out all options on how/when MC adds tags. So I want to tag the files before importing, then NOT writing MC any tags to it.
You would have to clarify the above if you wanted to talk about that though.