Outlook for Mac GUID issue

I am having an issue with my Outlook for Mac showing sent items before 7/17 as the GUID address. 

This is isolated to all emails before 7/17, and only for Mac computers. OWA works fine, PCs operate fine. 

We (my business) host our exchange email through go daddy, and recently went through a change from one account to another. So the emails had to be backed up via a PC using .pst files. Once the files were exported, the email address deleted and the new account created. I was able to import all of the .pst files to their respective email addresses.

The current issue started after this change. It is isolated only to Mac outlook on Mac. The issue also appears in the Mac Mail app.

I have tried recreating the email account in Outlook, no luck. I have spoken with Go Daddy for many hours and they do not have a solution for me.  

I am happy to answer any questions to help clarify this issue. I am looking to fix the way that outlook sees these sent emails and change them from the GUID to the proper *** Email address is removed for privacy ***.