Based on the description of your problem we have reproduced a situation in our lab where a request for 300 phones with realtime information will never return. This is a specific situation where more than 200 devices are requested and the RIS-Data request repeatedly fails. We will fix this bug in the next release.
Since a request for realtime information of a single phone also fails, we assume that the RIS-Data-Service on your cluster is not functioning as expected.
To further troubleshoot this problem we would like to ask you to inspect the SOAP-communication that occurs between CMShell and the host using the "SOAP-Monitor", a web-service that is deployed on your host. You can find this service here:
https://<Host Name or IP>:8443/realtimeservice/SOAPMonitor.html
If requested to login, you can do so using the same credentials as used for the CUCM administration pages.
If you now perform the same request for a single phone with realtime information again, a SOAP-request and SOAP-response should be logged for the Target-Service "RisPort". We would like you to report back to us with both messages.
Be aware that Cisco warns against use of the "SOAP-Monitor" on a production system to avoid performance impact. Alternatively you could use the Cisco RTMT or Cisco CLI to retrieve these messages from the logs.