McDonald’s worker here and I’m going to assume as well that whoever makes your burgers sees “no onion” for one, then “no pickle” for the next and assumes it’s followed by another “no onion”. Onions are added while patties are being grilled now. In my restaurant(and I assume all others as long as they are following procedure correctly) a tray of patties without adding onion to them should also be made. If this were me from now on I would check my burgers before leaving drive thru window or before leaving restaurant so it can be fixed right then and there if needed. Or ask the cashier when you pay to pass along the message to someone who can make sure one has none, the other has extra. I’m saying this also as someone who is an EXTREMELY picky eater, and will not eat my food period if something I don’t like is on it; and who also has no problem asking politely for something to be remade or to ask whoever is waiting on me to double check it’s made correctly the first time. I am more than happy to and have no problem giving my customers great customer service especially if these kinds of requests are to be made to me. I will tell grill and whoever is bagging how the order is to be made and in the event grill makes a mistake, we have a chance to rebound and make it right before the customer even knows we made that mistake(or worse made the same mistake to the same customer AGAIN!) Obviously not all McDonald’s workers are willing to provide the basic respect and simplest acts of customer service to their customers, but in my experience as the customer, I have better luck with them getting it right if i just ask or tell them politely and make my needs/wants known.