I've been here so many times and only had an issue once. If you mark an order as GF they replace the biscuit with fries. That time I also replaced the salad with more fries and they put a biscuit in it. Every other time I just explicitly say no biscuit and celiac disease and I've not had a problem since.
Honestly the food isn't out of this world but it's nice to have a GF option. The bread for the sandwich was terrible the one time I had it, but the chicken is good.
— Very
— Gluten-free items are marked on the main menu
— Most/All
— Good