Emails being sent with ? instead of apostrophe

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In some cases, emails that are sent out of Taleo have a question mark instead of an apostrophe (ex: Don?t vs Don't).  We see this when the candidate replies back to our email.

I did a little research and it could be a number of things (some of which we can't control) - but has anyone had this problem and found a good solution?  Thanks! Kim