What is going on when the tooltip first shows as blurry, then becomes clear? The most obvious example is hovering over the download button. Does CSS scale transform always behave this way?
In the 'download' button case, the download button is itself scaling up which makes the tooltip inside it scale up too. Thats the reason of blur (which comes with scaling elements)
I am seeing blurry text on every tooltip as it animates in, not just the one on the download button. I assume it is related to ClearType rendering the text on non-pixel locations.