It might be such a thing that the bearings have "seated" to the right (on a right handed bow) and cause the string groove on the cam to move closer to the limb (to the left). If the bores in the cams are slightly oversize, in time and shooting the bow,, vibration might be enough to shift the bearings in the cams. You could remove the cams and check with a micrometer, the width of the bearing races as compared to the outside thickness of the cams. It might be helpful to press out the bearings and replace them with Loc Tite or replace them with new bearings and Loc Tite to the correct depth,,,,,, IF the measurements are off and allowing this condition