Why don't you remove CUA from affected managed system while performing this step and latch again once this step is done ?
What is your system SP level ?
If note "2056893 - SAP Roles Not Copied to the Customer Namespace and Not Assigned To Users" is not helping, raise this with SAP.
Anyways, can you share complete logs on the error that you are getting and the places where are halted ?
Regards,