Hi Maria, I have got the same issue, it seems that in iOS app we have got bug depending on quantity of tasks in section. If quantity less then 11 function sorting hierarchy of field works not correct. I will try to create topic for asana dev team.
Here is my test case:
Here is sorting rule: priority field, then due date. Task with high priority in the top of the list. Take a look at “10+”, here is 11 tasks in the section Inbox:
As a result, the order was broken because of bug (tasks quantity less 11, now it 10). Take a look at task with high priority. It is not in the top now: