@rfindley A couple of points. First, if you pass a quiz from one source with errors, requiz it but don’t start a new round and switch to the other source while the Summary dialog is displayed, then the first round goes as expected, but on the second round it starts asking question from the previous source. Because original_items hasn’t been restored up to the second round from the other source.
Also, let me remind you about the click-to-open patch. And there’s a patch in that message that fixes the default speaker mode (Settings > Audio > Speaker > Rotate).