Variable glyph missing a chunk?

I am writing to report an odd issue that I have been getting building variable font for my typeface Fit using recent versions of FontTools (this was not an issue when I released the font in January).

I set up a test repo so you can see and duplicate the issue: https://github.com/djrrb/fit-vf-test

In the variable font, the bottom two points of my letter S do not move as they should, resulting in a chunk of the letter missing on the bottom lefthand side:

Those two bottom left points should remain at the left most side of the letter, like this:

I am reporting there error here rather than in the fontmake repo here because the fontmake-generated TTFs in master_ttf_interpolatable seem to be fine. The issue happens regardless of whether I use fontmake -o variable or python /path/to/varLib/__init__.py Fit.designspace to build the variable font.

Of course this could be an error on my part, but I appreciate any thoughts you might have as to why this might be happening…thank you for this and for all the progress that has been made in varLib!

[behdad]

I talked to Vinod on Monday. He said the big is fixed but it won’t be released too January. Maybe more community push can change that.

[anthrotype]

you can download a new build of fontview for mac with updated harfbuzz/freetype here (this one was built from Travis CI) https://github.com/googlei18n/fontview/releases/tag/v0.2.5