Stray "_top" anchor throwing off other diacritic

I have this situation where the dotbelow is far on the left:

Lowercase i:



When there is an anchor with and underscore or outlines (both apply here), Glyphs will not look further for anchors. So the ‘i’ has no bottom anchor.

I see, but why is it locked to the left position?

That is a good question. I have a look.

But you should fix the composition anyway. I would put the dot-path in a glyph called dotaccentcomb.i. Then the component can be auto aligned.