Hi Kevin,
this is what happened to me with Outlook 2013 and 365..."I have just checked the emails of a connected account. In the Outlook Web App, its timestamp displays the correct receiving time rather than downloaded time. If you are using Outlook client, I suggest you check whether the issue exists in the Outlook Web App. Its login address is http://mail.office365.com."
Why the discrepancy? Does recreating the account solve it?
Kostas