Chris, yes, the column value code was a relict leftover, I have changed it to the minimal code now.
In the early days of the new multi-value feature, I'm also stumbled about the different regulation or purpose between ', ' and '\\'.
Now I understand the function $meta_sep as a function only for displaying purpose.
Because in the Mp3tag user interface there is the double-backslash '\\' the only legal symbol for combining single items into a multi-value tag-field, I decided to use the double-backslash '\\' also when displaying a multi-value, especially in the list view, for the purpose to be able to make changes immediately there.
Why is that a problem? It's displayed the same in both the Tag Panal and the file list, is it not? Actually, it's the only way that I can see for it to work correctly, otherwise you get the behavior you see above: the fields being combined again.
What is the default definition for the ARTIST column? My installation is old, so I don't know whether I've redefined the value or not.
I think the problem (if there is one) is that when something like that gets changed, the setting doesn't get changed when upgrading an existing installation. No doubt this is to avoid changing the setting for anyone who has redefined it.
Another approach would be for the installer to change it if the definition remains the old default. I can't say for sure, though, whether that would be best.
Indeed for the installer not to warn and offer is highly remiss.
This secret change makes the program version number suddenly far less useful for support. For years going forward, helpers will have to ask users to root in the UI to find out what version's config they actually have. Or what fragment of it...