How old is your son? If he's too young for the bow he may torque it while drawing, making the plastic riser to warp. I think the designers should have provided the bow against such misuse because it's common with the kids, but who knows. Hope you'll get the bow fixed and your child will enjoy shooting it soon.
2008 Martin MOAB - 45-60#, set at about 51-53# / 55#" Perfect Line" compound/ 55# Mongol horsebow/ 45# "Perfect Line" takedown recurve/ 45# Bearpaw Grizzly hunter recurve/ 55# Samick Longbow Cheetah ... and several homemade bows