Small caps (SMCP) table is incorrectly set up. There is also no C2SC table in the font.

The small capital (SMCP) feature in the font file is not properly configured; it turns all glyphs, both uppercase or lowercase, in to small capitals, but only lowercase letters should become small caps when the text calls for it. See image below (the first letter of each word should remain uppercase). Additionally, it would be nice to add a caps to small caps (C2SC) table to the font's feature files (since the glyphs already exist, it should just be a matter of setting up the proper table in the font files).

Start by locating the font's feature files and reproducing the SMCP behavior shown in the issue image. Inspect how the existing small-cap glyphs are mapped, then verify that SMCP preserves uppercase letters and that a C2SC table is present and works for caps-to-small-caps text.

Written by the indexing model from the issue text.