Hrms FamilyPack G has been applied. From that moment on hrglobal is reporting problems on database items. Seems that there is now a new who-trigger on the ff_database_items table, but the code to decide whether to insert or to update the database item from the shadow tables uses therefore still the last_update_date. As such, every database_item is seen as a new one, so every time hrglobal tries to insert an extra row in ff_database_items, violating some constraints.
A quick fix in in the body of ff_data_dict resolved it. Now the tar.