Primary ID field is cleared on record inactivation

Hello!

We are using Siebel 20.10, however the below issue was observed also in previous versions (Siebel 8.1.13). We have configured a MVG field that is used to associated child records by using M:M relationship (intersection table exists). There is a search spec defined on the child BC to allow for selection only active child records (Active field has 'Y'). After the association is made according to the business process the parent record becomes read-only.

After some time the child record could become inactive. If we navigate to the parent record that has the M:M relation to this inactive child and press the MVG field the MVG value disappears -> this is expected as the search spec on the child BC filters all inactive records, however along with the MVG value also Primary ID field is cleared -> instead of Child's Row Id it contains "No Match Row Id". Even we re-activate the child record back it is not displayed on the parent record, because Primary Id field is still missing.