On my old star 4 occasionally I would have a ball bearing or two pop out and that would cause the string to slip everytime so If you know how many bearings are in there and if there visible or not. You may want to check that there all in there. They could have missed one during production.
4x PT57A Youtek PJ - Unstrung Spec: 331gr 303SW
Luxilon Alu Rough 50lbs - Babolat Star 5