Hi @Eleanor, thanks for the feedback.
Tasks are shown on due date on the list. If you set a start date, it'll show on 'Scheduled' type smart list with filter that includes start date. You can check more details on below post.
https://forum.goodtaskapp.com/t/scheduled-smart-lists-with-start-dates
For example, if you have a task that has start date of May 3rd and due date of May 8th, it'll be shown on dates between 3rd and 8th with due date showing 8th.
Thanks!