1. It’s most likely not a glitch, and this can be attributed to the menu item’s availability at the restaurant. Instead of deleting the item we just set it as unavailable.
    2. Depending on the familiarity with the menu or uniqueness of the item in question we can do some sleuthing and see if it can be made available for your order.
    3. You could be ordering from a place while you are not in the deliverable area for that specific outlet.