Maybe this is basically the same? Glyphs updates component glyphs only when showing them in the overview?
…but I don’t recall noticing this before for some reason in older versions (using 1213), I could be mistaken:
When I make a change to a base glyph (node placement, etc.), then the component glyphs using it, like the diacritics, don’t seem to update unless I switch out of the edit view and to the font view. And then they don’t always show in the font view until I either click on the component glyphs one by one or switch between masters and back. (This also seems to be the case in the preview panel in edit mode when I toggle between the base and component glyphs.)