I added a unique key column; seeded existing rows with unique values; regen’d; defined uniqueid expression on column; saved. No change in behavior.
Another clue:
I noticed with the table view behavior setting: Behavior section>Event Actions
I have it set pointing to the “Edit” system generated action, which results in the issue described above. However, when I changed this to “auto” – the selected row is displayed in detail with an edit action button to reach the form. Using the edit action button from this “intermediate view” functions correctly, i.e., the correct column values are displayed in the form. The issue seems to only happen when going from table view directly to form view via the “Edit” system generated action. And, I have not changed the “Edit” action parameters. Is a true/false expression needed in the “Edit” action perhaps…???