See the weird colors in the screenshot? This shows it was hinted. Now, I bet it was auto-hinted using an algorithm by Font Squirrel.
And yes, Typekit uses an auto-hinting algorithm too. That’s what caused this: https://typekit.com/fonts/vinter-web
Manually hinting each character at different sizes is long and tedious work and that’s why so many use an algorithm to do it for them. However, it causes problems with rendering. And this is why I advocate quality webfonts, so people don’t run into these issues.