In the array type questions we can select "Randomize on each page load" in "Randomize answer order" in the "advanced settings" to randomize the order of the displayed answer. If we set the question to Mandatory, and the survey taker does not fill in some of the subquestions, a new randomized order would be shown (with the "This question is mandatory. Please complete all parts." alert).

This seems to be the designed behavior, as the option says "on each page load". However, it would be useful to have another option that has the randomized order fixed for each survey taker, so that when the question is displayed again, the answer order would not be randomized for a second time. Thanks!