I don't know who needs to know this, but I just spent 6 hours figuring it out so someone might.
When you are importing a QTI zip file into a New Quizzes item bank Multiple choice questions will not import unless rcardinality="Single" is present in the response_lid field. It is listed in the QTI documentation as optional, for new quizzes it is not optional. It is optional for classic quizzes, but not for new. Similarly, for multiple answer questions rcardinality="Multiple" must be enabled.
Also, if you ask chatGPT to format a set of questions as a QTI XML it will probably not know to do this.
