Okay, first of all - the easiest way to do it is to simply rasterize the engrave once we have them looking the way that we want them to look. (The Glowforge does just as good a job with raster engraves as with vectors in this instance, so it’s quicker sometimes to do it that way if you get stuck.)
For this image, you would just fill the shapes and lettering with black, set the strokes for everything to null, select everything but the cutline outside, and then click on Object > Rasterize. You can use a high dpi (600) and you’re not going to be able to tell the difference from a vector engrave. Just make sure you Embed the image when you save the SVG file. (In the popup.)
Note: If you want to be able to change things later though, make a copy before you rasterize it and hide it off to the side so you will have one to change later.
Okay if you want to fix it via vectors, there were a couple of issues with that A and the B.
First I turned on the background grid so I could see where you had white fill and where the cutouts were performed correctly. You can see that the A consists only of strokes, no fill, and the grid shows through both shapes. The B has white fill in both the center sections and in the body, so those have not been subtracted out yet.
To fix these, you need to Ungroup several times and Release any Compound Paths so you can work from the bottom up.
For the A, I filled both shapes with yellow (so I could see them, the white is too hard to see for me), then I selected both and subtracted using the Minus-Front tool in the Pathfinder palette.
The B had a duplicate line for the base underneath it that was messing up attempts to do the subtraction at first, but basically, I just released the compound paths, made sure I was down to two center shapes on top of one base shape, then performed the Minus Front calculation twice. The first time that you perform it with one of the inside shapes on the base, the resulting compound path is going to move to the front, and you have to shift it to the back to use Minus-Front again with it. That’s just the nature of Illustrator, it can be a pain in the tush.
Once those were corrected, I selected everything inside the rectangle, gave it no stroke and black fill, and that is now set up to engrave correctly. The interface will correctly interpret that as an engrave because there is no stroke color associated with it.
I also took out a clipping path that was in there - they tend to cause error messages in the interface.
3-Engrave actual image copy.zip (6.0 KB)
You can see why it’s sometimes easier to just rasterize it.