PCM classes are being referred as external classes after importing into the system.
Because of that, I see issues like below for all PCM classes.

Class PCM-Data-PolicyDetails is mapped to table STAGE_CSRC_APP_ONE.pr_PCM_Data_PolicyDetails in PegaDATA.

This is an Obj-external class. You may access the class with Obj- activity methods.

Issue was due to obtaining the DB scripts (postgresql) from personal edition. Issue resolved after getting the DB scripts (Oracle) from actual system.