In Chrome, when I view the web page with a http:// address the text looks the way I like it.
But when I view the same page in https:// address that same text looks more bold (thicker). Why?
To test, try changing the custom font to something more exotic and noticeable. Or a safer bet if it’s a live site, change the fall-back font to a serif one, so you know that you are seeing it instead of the custom.