Speedy 300 etching where it shouldn't be

I'm trying to etch an image onto a piece of acrylic but whenever I run it I get a grid of dots where there should be white space. I've checked my source image and it doesn't have it, and cleaned my laser lens as a precaution. I'm not really sure what other troubleshooting steps to take, I haven't changed any other part of my workflow. Anyone have any advice?

I appear to have solved my own issue, for anyone curious even if you pre-dither an image before importing it into corel draw, apparently when sending it over to jobcontrol it can potentially be dithered in funny ways.