Sometimes limb twist is subtle, and it always helps to nip it in the bud, so it doesn’t get worse. I think limb twist happens a lot more often than most of us imagine. I’ve noticed bowyers examining a bow, sighting down the string, and giving the limb tips a little tweak one way or the other to get them in better alignment, even when there is no obvious limb twist.
The usual way to do this is to put one end of the bow on the floor and the other end cupped in your hand. You can raise and lower your hand as you sight down the string and recurved tips, looking for a slight bend in the string as it enters the string grooves. I raise my hand up high enough so I can center the string on the belly of the bow while looking at the relationship of the limb tip to the back of the bow. If the limb tip is not centered on the back of the bow while the string is centered on the belly of the bow, it indicates some slight amount of limb twist, which you can correct by bending the limb tip in the opposite direction and holding for a few seconds.
It helps if you can learn by actually watching a bowyer do this, but this is the best I can do in words.