There seems to be a weird difference between how Mp3tag encodes ID3 tags and how Windows does, where Mp3tag adds null characters between letters. I only discovered this because one program struggles to read the tags if I resave them with Mp3tag, and then can read them fine if I resave them with the basic Windows file property editor. Is there a way to prevent this happening with Mp3tag?
You can choose and adjust the encoding in File -> Options (Ctrl+O)-> Tags -> Mpeg in the "Write" section:
You need to find out, what encoding your struggling software expects: