There can be ways to hold your reins "wrong" (so to speak) in barrel racing.
Split reins aren't used for competition, although can be useful for training purposes.
If your barrel reins are too long, it will be putting your hands, arms, and body out of position.
If you are pulling your reins out to the side (elbow out), that is incorrect because it often causes your horse to lose their body position and collection. Keeping your hands in (pull your hand toward your belt buckle) and elbows in will keep you better centered.
Two hands or one hand is both fine. It depends on the horse you are riding, although you will typically see most finished horses being ridden one-handed.
As barrelracer23 already pointed out, we'd need to see video or pictures of you barrel racing to get an idea of what that other rider might have seen.
∞•*˚ Βгįťţαňγ ˚*•∞
It is not enough to know how to ride; one must know how to fall.