Looks like Safari is no longer rendering the fonts correctly. (It used to work but I hesitate to blame Safari because font files are complex and maybe there's a problem with the ones that I'm using.) I've dropped the custom font now.
Doesn't happen here (Firefox). Seems indeed like a rendering issue in your browser.
Hmm, must be Safari then.
Interesting. Looks normal for me on Chrome 50.0.2661.102m, Win10.