I have been visiting this chain for years, specifically the one in Honolulu. I asked the staff if the soft serve is gluten free and they said yes, all flavors are gluten free! I have tired the matcha, strawberry, ube, and black sesame, all without any issues. I just order the soft serve and request a cup instead of a cone. They also have drinks and shave ice but I have not tried those yet, would need to research the ingredients beforehand.
— No gluten-free information on the menu