What to do when a user's UPN does't match their primary email address?

Is there a solution to keeping emails in-sync with Dynamics Online and Exchange when the user's UPN doesn't match their primary email address?

Attempting to approve their email address results in an exception.

The SystemUser: 9b1ba778-d72e-e811-a977-000d3a1a7c04 email jeffrey.williams@MoneySolver.org doesn't match with UPN.