After a PII Scan, trying to "Register Data Model Tables" meets with the error:
The issue seems to be that the error occurs when the _backup tables are in the database. Remove those tables and do not get the error.
The backup tables only have the data, no FKs. The _backup tables are used for the actual masking. Have a script that replenishes these tables to retrieve production data and load it into the _backup tables.
Release : 220.127.116.11