Date format changed when appended to list

Date format changed when appended to list

Hi,

I have a dropdown list whose choices depend on user input of another field. The following code works fine. However, in our original data, the date format is dd-MMM-yyyy, but when the following code runs, the items in the list become yyyy-MM-dd.
  2. Clear Ideal_Start_Date;
  3. all_dates = Add_Upcoming_Cohorts[Programme == input.Programme].Start_Date.getAll();
  4. input.Ideal_Start_Date:ui.add(all_dates);
  5. show Ideal_Start_Date;
I have tried a few different things, but nothing works. 

Any advice? Thank you!