They used tapioca maltodextrin in early trials, but switched to corn maltodextrin before they shipped any commercial product. Sourcing is more difficult and pricing is much higher for tapioca maltodextrin than corn.
Maltodextrin is made from starch… The starch is processed until it’s about 15% of the way from starch to sugar. So maltodextrin is between sugar and starch.
If you allergy is affected by cornstrarch, then it will be set off by a formula with corn maltodextrin - but if your allergy is to something else in the corn, something that is not in the pure cornstarch, you’ll probably have no problem.
Interestingly, people who have peanut allergy have no reaction from peanut oil, because peanut allergy is to a protein in the peanuts… HOWEVER, you can never be sure how “perfect” the peanut refining process is. If there’s a bad batch that isn’t pure peanut oil, you can have a serious, serious problem. It’s a conundrum.