There may be a T2B delete error on from TA table T2B_CREDIT_CARDS to CRM table CREDITCARD with this error message:
The DELETE statement conflicted with the REFERENCE constraint "FK_REVENUESCHEDULE_CREDITCARDID"
This may occur on PP records as a result of the PL not being flagged when a change is made to the credit card info (like the expiration date being updated by charge processing). The PL needs to be flagged to make it update the CRM table REVENUESCHEDULE with the new CREDITCARDID. The errors should resolve the sync after those have been flagged.
If you are unable to flag records to sync backend yourself, then contact support to do so.