As I had assumed, your CUE file is
not Unicode/UTF-8, but plain Latin-1
On an English or German version of Windows (actually many more), the Latin-1 Codepage is configured as the "local" Codepage by default.
That's why, on such systems, decoding the file with the "local" Codepage gives the desired result. And one might assume that this is always the case.
But it's not! Other localized versions of Windows have a different Codepage configured by default, giving potentially very different output
Solution: Open the CUE file in Notepad++, change the Encoding to the suitable one (here Latin-1) and then
convert to UTF-8 (Unicode),
with BOM.