I just found that kerning pairs with no kerning class might get scrambled when exported to variable fonts. Sometimes kerning pairs of extreme masters might use the value from an intermediate master, and other time the kern values would just get completely “randomized” on one or more masters.
Exporting non-variable ttf/otf won’t have this problem. Currently the only way I found to hack around this problem is by adding kern classes to every kern pairs…I wonder if there’s a faster way to do that?
Do those glyphs have kerning groups assigned. It can be problematic if in some masters, the you have group kerning and in others, you have glyph kerning.
And what version of Glyphs do you use? Can you try the latest cutting edge version (activate it in Preferences > Updates).
Yes I found that for it to work properly, all kerning pairs have to have kerning groups and with the lock locked. Kerning exceptions would also cause some problems for variable fonts.
I’m using the latest normal version of Glyphs, I’ll try the cutting edge version later
As long as all master have the same setting, it should work.
What version of Glyphs do you have?