It works fine in Glyphs 3.
Disable coroutines set to on in the font info window.
Export custom parameters set to Decompose components in font info window.
Remove Overlaps on in the export window.
Outline Flavour TrueType in export window.
File Format .ttf in export window.
Autohint off.
The ttf produced from Glyphs 3 is on the left, and Glyphs 4 on the right.
