This is an interesting error. You are correct that the SQL System DB's are replicated by CA XOSoft, which would include the SYSSERVERS table within the MASTER database. The error you are recieving is referencing the SRVID field and the Severname for the same record. This is most likely the reesult of an RPC call referencing SRVID = 0 in the SYSSERVERS table which is then referencing the wrong server name. You can manually add the record to the DB using the SP_ADDSERVER stored procedure. Add the servername of the Replica server.

You mention that you're using CNAMES. a CNAME would point to an A record in DNS. CA XOsoft modifies the A record of the Master Server when Redirect DNS is configured. I suspect this may be part of the issue as well. I would properly configure my applications and clients to connect to the A record. IT is not necessarily required but it causes less confusion in the long run. In your configuration, the clients are pointing to name 'A', which is a CNAME resolving to a differnt A-record 'B', which is then resolving to the IP of the Replica 'C'. CNAMES are convenient, particularly for migrations, but are frequently a lazy way to redirect applications and clients following a migration when we either don't want to or don't know how to manually reconfigure the applications and clients properly.