is it normal that walkman and system doesn't support same language?

[scoolmanDT]

I flashed my W580i with
W580_R8BA024_FS_TAIWAN_RED52
W580_R8BA024_MAIN_TAIWAN_LA_RED52
W580i_CDA102774_6_R2A_Customized_Taiwan

so that I can display Japanese characters on my phone.
Everything was fine, but I find it weird weird that the file manager of the phone is able to display Japanese characters and Unicode characters correctly, while Walkman display "????"question marks for all Japanese characters and "square" for all Unicode symbols such as 「☆」 and 「♥」

Is this normal? Or does this mean that flash failed?