Since the two screenshots appear to be from entirely different documents, it's impossible for me to see what 'font corruption' might have occurred. That said, it seems one system might be configured for English (US) use and the other for Japanese use, in which case some of your issues might be due to that. A simple workaround might be for each user to save the documents as PDFs and exchange those rather than the documents themselves.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]

I just now learned that the problem is display screen-only and that all of the documents print out correctly. In view of this, it seems that it's a screen font issue.

In view of this, do you have a suggestion as to what to do next?