Thought you might want to wrap it up
In a perfect world I think I would still prefer a way of limiting the view to just the invalid ids, but I can appreciate as per your initial response this isn't something easily possible currently. The disadvantage of the highlighting approach is that it requires leaving the view in "highlight mode" while the user works through those rows, and then they need to perform an action to get back out of it and return to normal searching. I've got a keyboard shortcut in my plugin to toggle turning highlight mode on/off. However there is no visible indication in the main gui as to whether you are in highlight mode or not (you have to drill into the search preferences dialog) so that is a little icky. I think as a user I might have preferred the checkbox (or a toggle button) on next to the search box as it used to be as it least you could see what "mode" you currently are in.
With that all said, as you have the N/shift-N keyboard shortcuts to work through the results it functionally does the job. It just isn't quite as nice imho as limiting the set of rows to just the ones you are interested in rather than jumping all around the results, particularly since there is no way to sort to show the highlighted rows at the top.