1.block your crossbow level. Put a level on each cam 90 degrees to the rail stock. Both level readings should be the same (level).
2.for cams not to be level, the "Y" end of a cable is out of adjustment due to: one side of the cable "Y" stretching, improper leveling, a bent axle or faulty bearing if the crossbow cams have them, a weak limb or mismatched limb deflection (one limb stronger or weaker than its partner). The Barnett Ghost 410 came with poor quality cam bearings and the bearing axle hole was too large. Replacement bearings came the same so I installed a full one piece bushing with the proper axle hole.
3)if the a cam has enough lean, when the crossbow is shot, the bow string can come off which was the problem with the 2018 Barnett Droptine STR. Correcting this manufacture tuning error, no more problem.
4)Installing high quality cables (built under enough tension and properly served), proper tuning will correct this providing: the limb deflection is the same, no bent axle or faulty cam bearing. Adding 1/2 or full twists to the proper "Y" section of the cable will make the correction. If a cam tilts down, add 1/2 or full twists to the bottom of the "Y" section. If the cam tilts up, add 1/2 or full twists to the upper "Y" section.
5)other members that have had experience with different brands or series of crossbows can probably better answer this. My experience is with the following Barnett crossbows: Barnett Ghost 410, Barnett Buck Commander BCXtreme 365 Ultra Lite, the 2018 Barnett Droptine STR and the Barnett Whitetail Hunter STR Pro.
All the best.