Unicode cuesheet write problems

I have a UTF-8 cuesheet with the following information: (upon previewing this I realize that some characters are already being lost)

REM DISCID 910C270A
REM COMMENT "ExactAudioCopy v0.99pb5"
PERFORMER "Janáček, Leoš"
TITLE "Věc Makropulos"
FILE "janacek2==01-04.flac" WAVE
  TRACK 01 AUDIO
    TITLE "Nu? Slyšíte?"
    INDEX 00 00:00:00
    INDEX 01 00:00:32
  TRACK 02 AUDIO
    TITLE "Buenos días, Maxi!"
    INDEX 01 05:25:05
  TRACK 03 AUDIO
    TITLE "Pečítko s iniciálkou"
    INDEX 01 09:05:00
  TRACK 04 AUDIO
    TITLE "Pro lékaře!"
    INDEX 01 21:14:22

This loads into mp3tag fine (i.e. it reads and displays all special characters) but when it goes to write tag information to the cuesheet, any unicode information in that tag is destroyed.

For instance, "Janáček, Leoš" is changed to "Jan" in the mp3tag window, and there are nonsense characters in the cue sheet itself.

Is this a known phenomenon, and is there a way around it?

There is definitly a problem with unicode characters, I can confirm this. But it looks to me as if this problem exists only in the Album Performer (ALBUMARTIST) field.

See also here: [F] cue files are not read when they don't start with TRACK 01 AUDIO