To hack the problem, instead of the big rectangle with a hollow space, I specced four narrow rectangles next to each other like lincoln logs (in Illustrator). So now the SVG should be four different filled rectangles that look to the eye like a frame.
But it’s burning the same way, painstakingly going from the left rectangle, all the way across to the right rectangle and back, instead of zipping the left burn then jumping and doing the right burn.
Does that make more sense?
it seems dumb about where the burning is, and instead is acting like it’s doing a jpg, ‘burning’ the zero parts as well.