The return time for Jolly Holiday can get quite long on a busy day. And high demand items are often only available through mobile ordering earlier in the morning. (Similar to during the holidays when the gingerbread men show up on mobile only for a few minutes). So if you don't see something later on the app, it's not necessarily that it's unavailable. You just have to line up in person for them. Sometimes if I know I want something for later or to take home, I order first think in the morning and edit the time for later in the day.
Somewhat related, currently the Japanese cheesecake (yummy if you like that type of texture and not-so-sweetness, which I do!) at Aunt Cass Cafe is not on mobile at all, unlike the other menu items. So unfortunately if you want to try it, you'll have to join the line.