I’ve been having issues where Suitcase is auto-activating the wrong font, such as activating the italic version of a font instead of regular. I’ve narrowed it down to being an issue with Google Fonts. In Suitcase some Google font styles are named the same, for example, Josefin Sans Regular and Josefin Sans Regular Italic are both named “Josefin Sans Regular”. This causes the wrong font to be auto-activated by Suitcase. The fonts appear to be named correctly on font.google.com.
In the attached screenshot you’ll notice that three of the weights/styles for Josefin Sans are named the same: Josefin Sans Regular/Regular Italic, SemiBold/SemiBold Italic, Thin/Thin Italic