If you look at the footer on this page here in Safari, then look at the same footer on any other page, you'll see a difference in font rendering. It looks the the font smoothing is being applied twice to me.
If I turn off the Google map, then the font rendering returns to normal, so I'm confident the map is at the root of the problem.
I am applying a transparent font shadow to all text to fix some @font-face rendering issues (artefacts mainly), but this problem is present with or without text shadow.
It's a Mac only problem.
Has anyone else come across this problem? Is there a known cause and/or fix?
I've been tearing my hair out with this for the past few hours. You can fix it by adding
-webkit-font-smoothing: antialiased;
to the offending selectors.
I hope this can save someone else the time and stress it caused me.