Feel the thickness of the limbs, not only along their length but also side to side. If the limb are moving to one side or the other as time goes by it is an indication that the limb thickness, from side to side, is uneven making one side of the limb stronger than the other and pulling the limb to the weak side.
Heating and bending will bring the limbs back into line but if they are uneven they will go back to where that were before. You have to "fix" the problem to get good results.