Hi! I noticed that instance and special layer interpolation sometimes uses wrong masters.
I thought it was Glyphs 2 not supporting that many axes, but turns out Glyphs 3 have the same problem.
Basically, it ignores the intermediate master between two extremes (‘Normal’ width in this case). Sometimes.
Attaching a file with some instances, check out their interpolation, I added notes to instances names, hope they make sense.
Interpolation Bug Test.glyphs (109.1 KB)
font = Glyphs.font for instance in font.instances: interpolation = instance.instanceInterpolations print( instance.name ) for masterId, value in interpolation.items(): print( font.masters[ masterId ].name, value) print('')