Text not displaying correctly in PDF via 1 Email service, but fine in another?

I set up a report in FileMaker that is run every Friday and then emailed as a PDF to several remote users. One user has had repeated trouble viewing the report from his ATT account, but is able to to view it fine from his company account. The issue was most of the document was displaying, but certain parts of text were showing up blank. I first thought it was the font that was being used, so I changed it to Arial (b/c what is more standard than arial?). But, sure enough the next week he is still having trouble. This seems so odd to me…none of the other remote users are having this difficulty.

I might end up having him access it through the company account only or something else, but I would prefer to figure out what is going on because it seems so odd.