3.5.1 (3534), exporting a static OTF.
I have a kerning exception/seven.numr/fraction = −310. The right kerning group of seven.numr also has a class pair against fraction of −290. Edit view correctly shows −310. In the exported font the two values are added, so InDesign and HarfBuzz apply −600.
The compiled GPOS kern feature has two pair lookups, and both are registered for DFLT and latn:
| Lookup | Subtable | Value |
|---|---|---|
| 0 | Format 1 (glyph pair) | seven.numr fraction −310 |
| 1 | Format 2 (class pair) | @[seven.numr group] fraction −290 |
The exception and the class pair are in different lookups, so the exception doesn’t override the class pair and both apply.
The right group containing seven.numr mixes Common-script glyphs (numerators, superiors, asterisk, degree, registered, trademark) with Latin-script glyphs (ordfeminine, ordmasculine). Seems like Latin members cause the group’s class kerning to go into a separate script-specific lookup from the Common-script exception.