Updates performed while the Load Data Warehouse (DWH) job is running will cause the error indicated.
In the example error, the DWH_INV_IDEA load is not picking those up which language table DWH_INV_IDEA_LN, has picked.
ORA-02298: cannot validate (PPM_DWH_OWNER.DWH_INV_IDEA_LN_FK1) - parent keys not found
If the issue happens, immediately pause the job and run the following query:
select * from dwh_inv_idea_ln where investment_key not in (select investment_key from DWH_INV_IDEA);
Release : 15.8
Component : CA PPM DATA WAREHOUSE
This is reported as DE61075, under Engineering review.
Reference: Load DWH job frequently reported issues