Answer
This is a master-detail binding that hasn't been configured — simply adding an entity/association to a page doesn't automatically filter or bind its content to the parent record being viewed; you need to explicitly create the binding connecting the List/Group to the parent context (typically via a Selector) in Aurena Page Designer. Follow IFS's Master-Detail Associations / Building Master Detail Relationships documentation for the specific binding steps — without this explicit binding step, an added List will show its entire unfiltered dataset, and an added Group tied to a Custom LU can show completely empty content for every record, since neither knows which parent record's data it's actually supposed to be scoped to.