When you copy & paste a component whose auto-alignment is disabled (either at the time of copying or font-wide from font info), the pasted component also brings the width info together, changing the width of the destination glyph. This only works for a blank glyph; if there’s already a component or outline, the width will stay the same. My question/suggestion is, if the component is not auto-aligned, why is the width inherited (and only initially)? I think it make sense to not affect the width at all.
A similar/opposite/related point: when I open a new glyph and add a zero-width component, the new glyph changes to zero-width, and the default is auto-aligned. But when I go to another master in the new glyph and copy-paste the same zero-width auto-aligned component, the width doesn’t get zeroed. In a font with many masters, this seems like unnecessary work.