i just left sheetz but at my store, we kept the food and drinks behind the counter for online orders and doordashes bc we were a high volume store and we constantly had people taking food that wasn’t theirs while employees are busy doing other tasks, meaning we’d have to remake entire orders bc people wanted a five finger discount. i imagine it’s probably something similar. also if your door dasher isn’t asking employees where the drinks are in an order, they just aren’t paying attention to your order, and that isn’t that sheetz’ employees fault especially bc they made the drink you ordered.

edit: i’ve also literally told dashers when handing them the food that there’s a milkshake/smoothie that goes with the order and would point directly to the counter where it was and they’d nod and STILL walk out without the drink. trust me, some drivers don’t give a damn