Has anyone experienced hz_parties table not be in synch with active person records?

Summary:

Scenario: Classic HR Help Desk - Agent goes to send response message to the Primary Point of Contact, however the email can't be found and we get a warning that some of the recipients either don't have email addresses specified or there is a problem in HCM and TCA sync for them (SVC-5295501). We are running the Synchronize Person Records process once a day. Oracle says that the hz_parties table is missing emails that exist on the active person records. We still don't know why the hz_parties table is not updated with the email that exists