For years, the load library for IPC has been included in both the STEPLIB and DFHRPL of the CICS started task. Can you verify if the loadlib needs to be in STEPLIB, or only in the DFHRPL for CICS?
Component : IPC
Because the IPC loadlib does not need to be APF authorized (see Knowledge Base article 102416, titled "APF Authorization not needed for IPC Loadlib"), it does not need to be specified in the CICS STEPLIB, only in the DFHRPL concatenation. Typically, the CICS Steplib will contain the IBM CICS Product loadlibs, Language Environment loadlibs, and any other application or system loadlibs that require APF authorized functions.
Refer to Post-Installation Steps
As always, please contact Broadcom support for Datacom if you have further questions.