Glyphs 3: Vertical alignment of mirrored copy of letter off until "Disable Automatic Alignment" is activated

I have a d and q that are just mirrored components of b and p. Changing the vertical positioning of b and p did not change the vertical alignment of the component-based letters until I disabled automatic alignment (and then promptly reactivated it).

This seems like a very unintuitive behavior, and I’m not sure how it makes sense—but maybe it’s useful for other component uses?