Random Layer lines appear in vase mode

Guys what should I possibly look into, this print is ment to be a vase mode print but occasionally there would be these layer shifts for a single layer and then it resumes normally.This effect is not there is back right corner and it is present every where else Printer Vcore 3.1 500x500x500 speeds 35mm/s layer thickness 0.4mm Any help would be great! TIA