Jasoroony is totally right about the LCD. I’ve posted in the past about how you can see the movement stutter coinciding with the display updates on the LCD. I’ve disabled the updates on my firmware to get around this but I never noticed that it caused the issue with lines running out of the image. Possible for sure though. Have you tried increasing the acceleration values? You can do this with preprocessor gcode so to don’t need to change in your config. H. This timing mismatch between the fan control and the steppers shouldn’t be noticeable in the burned image but it would be nice to see it fixed. I’ve modded my own firmware for increased pwm resolution and better timing . I’d post instructions but I know they’ll be impossible to support with new Marlin releases coming out on a regular basis.