Bug: Preview doesn't correctly interpolate corner components of compound glyph

[kontur (Johannes Neumeier)]

In a font with three masters I have an i composed of a stem, the tittle, and the stem in turn has a corner component for a serif.
When viewing all instances of the i in the preview only the masters have the corner component correctly rendered, while the interpolated versions show the stem without the corner. Viewing the stem or corner component previews correct interpolations between the masters of that glyph.

i with missing corner interpolation of the stem’s corner component

Correctly interpolated preview of the stem, including its corner component

Corner component with correctly interpolated preview

This affects only the preview, and the exported font has the correct corner component in the i. I’m not sure whether or not it is pertinent that it’s a nested corner component.

[GeorgSeifert]

Is the serif compatible? What version of Glyphs do you have?

[kontur (Johannes Neumeier)]

The serif appears to be ok. It has reverse path order in all three masters, starting from the top right point, and the lines connecting the different nodes connect where they should in the “Show Master Compatibility” view. My Glyphs is Version 2.4RC (935).

Edit: Here is a empty file reproducing solely this issue:
corner-bug.zip (3.1 KB)

[GeorgSeifert]

I’m on it.

[GeorgSeifert]

Fixed it.