Hi Beth and drlara
If I was giving you feedback I would say you are both correct but also both incorrect!
e.g. yes in normal mode the quiz in Xerte is meant as an informal knowledge check yes it's true that learners can respond to each question until they get the positive feedback. You could leave the individual feedback empty but one of the positive things about Xerte is that you can put contextualised feedback for each question and each response in that question.
Where you're not quite correct is that there is an option for the whole LO which will change this behaviour. If you were to export your LO and quiz as SCORM and import into an LMS/VLE you will notice the quiz and some other interactions behaving differently and you can simulate that with an optional property at LO level. Select the first icon in the tree and add the optional Tracking property. Then tick the box to Force tracking mode behaviour. This will mimick the SCORM mode even when viewed via preview or via the public url. You'll then see that as you answer each question the radio buttons are disabled and you see the relevant feedback.
When exported as SCORM the tracking of first pass or tracking of last pass will also come into play however via the public url it will still be possible for the learner to navigate past the quiz and then back again and retry the whole quiz. But again that's because it's usually meant as knowledge check rather than formal assessment and even if we somehow prevented that the learner could simply refresh to try the quiz again too.
HTH
Ron