When the restaurant says " they already gave the order to another Dasher " what really happened?

This happen to me few times last month on late night orders at the drive thru...

I'm about to pick up the order , but the employees tell me they already gave out the order to another Dasher.

I call doordash and the customer. I text the customer , DID ANOTHER DRIVER ALREADY DELIVER YOUR ORDER? The customer replies your my only dasher and their still waiting for the food..

Then I call support and tell them about the situation and they ask me IF I CAN GO BACK TO THE DRIIVE THRU ....BECAUSE THE RESTURANT WILL REMAKE THE ORDER AGAIN...

So are the restaurants lying? They accidently gave my customer's order to another Dasher ? Or they just don't want to make it or something ?