I believe it is a problem with our QA installation of Apex. It appears that constraint (foreign key?) is missing. wwv_flow_worksheet_cond_fk is missing and appears to have an effect on pages with Interactive Reports.
I want to get the environment rebuilt (Fresh Apex install, import workspaces from DEV) but that means users, developers and DBAs need to be involved and a formal plan, communication, and change requests need to be made to ensure it is done with minimal disruption.