Hi Angela

The suggestion was made to simulate an all or nothing question where all of the options need to be correct to be awarded 100% and 0 otherwise.

Only the first option in the multichoice question that has all of the required  answer combinations would receive a grade of 100% the other options would receive a grade of 0% so wouldn't reach the quiz pass mark.

The all or nothing question is a third party plugin so it is not in Totara's control . This plugin was confirmed as working in Totara 13 so if this behavioujr is required then this can be used . If the bug with this plugin is back in Totara 15 then the provider of the plugin needs to be contacted to fix rather than Totara

regards