The contents of the files submitted with the assignment are displayed when grading, but Japanese characters in the files are garbled.
It does not occur in PDF, but it occurs in TXT, DOCX, XLSX, PPTX.

Steps to replicate:

1. Log into a site using version 3.5.3 and has Japanese language pack installed,
2. Create an assignment and submit a word doc with Japanese characters,
3. Click on view all submission and click to grade submission containing the Japanese text,
4. Notice Japanese characters are displaying as boxes.