After opening a ticket with Cisco, the CUIC auto redirection is not a behaviour in CUIC version 10.X for these reasons :
Please note that this behaviour is expected because of the following reason:
In 9.X and below, you would log into UCCX master for CUIC and it would redirect you to the UCCX sub for CUIC so that the UCCX sub handled the DB queries.
In 10.X and above, live data was introduced to CUIC. The Real Time Reporting (RTR) subsystem on the engine (ICD_RTDM traces) calculates live data only the UCCX master. For this reason, we do not redirect from the master to the subscriber. We need to be on the UCCX master for CUIC to see live data reports. When running historical reports on the UCCX master of CUIC, CUIC still sends DB queries to the secondary UCCX server's DB, so there is no negative impact for this change.