Importing a font into an existing multiple master font as an additional master font can change the order of some, not all, paths and components in the new master. This occurred in the App Store version of 1.3.7.
This was my process:
- After checking compatibility of my two masters I exported them to UFO files.
- I used Superpolator to create a new intermediate master. This was necessary because the contrast of the two masters differs greatly and I needed to use Superpolator’s anisotropic interpolation to thicken the horizontal stems.
- I created the new master UFO in Superpolator. This new UFO file is compatible with the existing master UFO files.
- I opened the original MM font and the new master in Glyphs. Then I imported the new master into the original as an intermediate master.
- Dozens of glyphs are now incompatible because path or component orders in the intermediate master have changed.