ital=1, not remain upright.Current behavior
font-style: italic is mapped only to the slnt axis. An ital-only variable font remains at ital=0.
Expected behavior
The italic keyword uses ital=1. Oblique uses slnt and keeps ital=0.
Lines: ital-only + italic; ital/slnt + italic; ital/slnt + oblique. Red pixels in Diff mark the affected build's mismatch.