Yes, those ripples are strange. Did you use a regular fine point Sharpie or an ultra fine one? Just trying to get an idea of the scale of the ripples in the photo.
How are you generating the gcode from the SVG files? Can you preview/simulate the gcode? Can you use another method to generate a simple 45 degree box and circle outline in gcode just to cross check the software? I’m, kind of reaching for ideas right now.