Illegal line segment point count message

Hi, I am trying to export the Grenze fonts [https://github.com/Omnibus-Type/Grenze/tree/master/sources](https://github.com/Omnibus-Type/Grenze/tree/master/sources) from fontmake, like we did before when we used a build.sh file, and this time with config.yaml it gives me the following error:

```
File "/Users/yorlmarcampos/Documents/GitHub/Omnibus-Type/Grenze/env/lib/python3.7/site-packages/fontTools/pens/pointPen.py", line 201, in _flushContour
assert len(points) == 1, "illegal line segment point count: %d" % len(points)
AssertionError: illegal line segment point count: 3
```
and then this:

`fontmake.errors.FontmakeError: In 'Grenze.glyphs' -> 'master_ufo/Grenze.designspace': Generating fonts from Designspace failed: illegal line segment point count: 3`

will there be some way to determine and show which glyph is causing the problem?

Thanks in advance!