Assistant: Corrupted glyph for lowercase 'j' in Regular and Semibold weights

**Describe the bug**

The Assistant font family has a corrupted glyph for the lowercase letter 'j' in the Regular (400) and Semibold (600) weights. The letter 'j' renders visibly bolder/heavier than all other lowercase letters, creating an inconsistent appearance in body text.

Browser console confirms glyph corruption with the following warning:
downloadable font: glyf: empty gid 410 used as component in glyph 16

**To Reproduce**

1. Download Assistant Regular or Semibold from Google Fonts (https://fonts.google.com/specimen/Assistant)
2. Convert to WOFF/WOFF2 or use the TTF files directly
3. Apply the font to text containing lowercase 'j' characters
4. Observe that all lowercase 'j' characters appear bolder/heavier than surrounding letters

The lowercase 'j' should render with the same weight/boldness as other lowercase letters (a, b, c, etc.) in the Regular and Semibold weights. See highlighted j from demo.html

**Additional context**

- Issue confirmed across multiple browsers (Chrome, Firefox, Safari) and operating systems (macOS, Windows)
- Issue exists in both official Google Fonts downloads and third-party font distributors
- Issue exists in both TTF source files and converted WOFF/WOFF2 web fonts
- Other weights (Light, Medium, Bold, ExtraBold) do not exhibit this issue
- Console error specifically references "empty gid 410 used as component in glyph 16"