Why isn't my new font displaying correctly on mobile?

Store Design
1

Hello, I am using the impulse theme and changed my font and it appears fine on the desktop but on the mobile version the font isn’t the same, on the mobile the font is in bold. I’m trying to use the Josefin Slab font (semi bold italic)

my shop is st-louie.com

2

@sunshine007 - where exactly is it bold?

3

On the mobile app the body text is in bold, the name of the product and the
product description are in bold.