A PlainText preview is garbled when it includes non-ASCII characters encoded with not UTF-8

[Atsushi]

We have a problem that ACS preview functionality provides garbled results when a plain text document has non-ASCII characters encoded with not UTF-8. We have ACS community edition 7.3.1, 7.4 and 23.1 and this happens in all versions.
Even if the same characters are included in a plain text encoded with UTF-8, transformed result in preview window is correct (not garbled)

Of coursse, if this document is not a plain text but a MS-Word or so, such garbled result will not be provided.
In my understanding, the transformer is libreoffice in case of transforming from plain text to pdf for preview window. But I confirmed libreoffice on server could open this plain text file with non-ASCII characters(Japanese) encoded with Shift_JIS properly...

Much appreciated if you give us supportive information to resolve this... Or clarify whether this is a bug or not.

#Garbled preview result in case of Shift_JIS encoding plain text#Correct preview result in case of UTF-8 encoding plain text

[Atsushi]

Can anyone provide information about this? I attached the log file when this document was converted to pdf after creating a new version (ACS23.1). 

Transformed log