Slash (/) characters in file names gets converted to a semicolon in the file name field

[Thain]

As title goes. Screenshot attached of a Finder window in front, and Mp3Tag in the background.

(I just added a slash to a random file as an example, I see it happen with all of them)

Mp3tag 1.11.0 (134), MacOS 26.3.1.

[Florian]

It looks like it's the classic colon issue with macOS and Finder. Here is a little more context and explanation to it:

Why is MP3 Tag Replacing Chars

It's a thing specific to macOS and Finder. The filenames actually use the colon character : (as displayed correctly in Mp3tag) but Finder does some auto-translation into the forward slash /. You can verify that yourself by opening Terminal.app, navigate to the Disc 5 folder, and use the command ls -la to list the folder contents. More on that here:

[Thain]

Huh, TIL! Case closed I guess.