We work hard on the issue but found that safari is able to display the cloud properly but not always (the less tag in cloud the better to not increase odd). This is clearly an issue in Safari Webkit rendering library, something we can bot solve on our side.
We tried many things, by changing CSS or the way we load google webfont without success.
There is a workaround, but at the cost of webpage design. We could detect safari and stable google webfont. This make the cloud more readable, and will load faster on safari mobile.
This could be delivered in version 3.0.10, what do you all thinks?