Bug: Corner components disappear when using Subtract front path

I’m finding if I use the Subtract front path shortcut at the bottom of the Transformations panel, the corner components I’ve used elsewhere on the same glyph get decomposed.

EDIT: in fact other overlaps are removed, and smooth (green) nodes turn blue, too.

The other overlaps have to be removed as it would give very strange results when the overlaps are subtracted. I’ll have a look if I can improve that.

I’m not sure I follow what you’re saying, but at any rate I want to clarify that the overlaps and corners that get lost are not in the region I’m subtracting, but way over on the other side of the letter.