Did you check your Z axis step? I 'm not expert, but I read it’s a good thing setting layer dimension as a multiple of the single Z step distance
@Dario_Marrini yeah, that’s all set correctly
The banding is so regular it almost seems like a post processor is including a regular offset deposition layer. I apologize I’m a novice with 3d printers. I’m giving you ideas maybe one will help. What is the gcode program? How many layers between the bands? The motor in z could be holding a lower location compared to the programmed height in that stepper freq range.