Custom font not loading properly

I have uploaded one of my brand fonts to SquareSpace using SquareSpace's instructions. At first it looks fine but then it starts adding kk instead of specific characters, such as apostrophes. If I go back into "Custom CSS," it will look how it should at first and then a few minutes later it goes back to the kk characters. Does anyone know what the issue could be? My website is sarahstarrs.com

(Screenshots attached to show what I mean)

Hi,

I think because font files itself. Have you try contacting Font Author to ask this? If they can't help, let me know, we will check it again