How to get LB to preserve transparency when engraving images

Hey guys. So I was trying to engrave an image and decided that instead of wasting a couple hours engraving the useless background that I’d cut the majority of it out and have a short transparency gradient around the subjects of the photo. Lightburn seems to see and acknowledge the transparency, but I can’t get it to actually engrave it (see image for how the image looks vs what the software is sending to my engraver). Any idea what I’m doing wrong? Thanks in advance.

Bumpy bump…