403 error loading a standard shopify font on my site

[Ombelle]

Last week, i noticed my site was not loading the fonts that shopify provides. One of the font is firasans

I see a buch of 403 errors on the console. When i try one of the links myself, it tell me there is a problem with the hmac. 

I did not do any change 

[Ombelle]

Ok, yesterday, one of my employe added some content on a leaf page and the font problem went away. Weird