Calibri font inserts extra characters into PDF version of report

My company has several reports that are generated using the Calibri font. We've had several users tell us that their reports are showing extra characters - specifically, it inserts the letter "i" after every lower-case "t". For example, Scott becomes Scotiti and Tether becomes Tetiher (there's no letter "i" inserted after the capital "T" - it only inserts after lower-case).

We've determined that the problem is due to the fact that we're using the Calibri font; if we use a different font, it works fine. Also, if the end-user copies text from the generated PDF and pastes it into another document, it renders the correct spelling. So for example if they copy "Scotiti" out of the PDF and paste it into Notepad, it shows "Scott" as it normally should.

The obvious solution would seem to be changing the font on all of our reports to something else, but unfortunately we have hundreds of reports scattered across a half-dozen sites, and we would rather not have to change each and every report.

For the sake of completeness, I updated the Adobe Reader on one of the trouble machines to 9.1, and the problem still occurs.

Is there a way to fix this?