In doing a small world map for a cup stamp in 4 layers my Y axis sometimes burns part of the image on a layer ok but part of it comes out about a little north or south with a gap between them. I can correct it by reducing the speed or the passes (4 passes @ 35 in/min. changed to 2 passes @ 10 in/min.). The distortion is not consistent. It might be a little different each time. Other layers occasionally are a little off center, always in the Y axis. This seems to be a new development. Belts are tight enough. I grouped all items together in affected layer but distortion was worse.