LightBurn’s SVG import was written from scratch, by me, and supports only the parts of the SVG spec that I’ve seen actually used in the wild. No one creating artwork for CAD uses px as a unit, because that’s display resolution dependent.
Your SVG width & height values are indicated as “100%”. “Normal” SVGs are specified with real units, so that’s likely the issue. I don’t think I’ve ever seen an SVG with size specified this way.
Images are always drawn as black and white - they’re just outlined with the layer color when selected, otherwise they look strange.