Record created through portal acts unrelated
I have a portal on a parent table through a one-to-many relationship that allows records to be created on the child table. When I enter a name in the portal for the child record, the record is created and I can click on my GTRR button on that portal row and be taken to the new record. When I get to the child record, the primary key match field that the relationship is based on shows the correct ID# for the parent, but the records don't appear to actually be related! None of the merge fields that reference the parent are filled, and the GTRR button to return to the parent doesn't respond. If I "modify" the primary key match field (click into it, add a space and delete it, then click out) without changing its value, suddenly the records are related properly and everything works like it should.
I can think of a number of different scripts to work around this, but it seems a little more fundamental than something I'd want to just cover up. So if a simple "modify" action on the key field can make it recognize the correct relationship, why aren't my new records just related properly from the start? Any ideas?