Solution : https://service.sap.com/sap/support/notes/1487234 (SAP Service marketplace login required)
Key words :
The settings of Windows and SAPGUI Font character set is shift JIS, which is only for JA character Note 764480 helps to narrow down the possible cause.Note 508854 describes how the settings should look like.
Related Notes :
| 753381 | Classification of character damage |