ripple animation causes the implicit change of font weight on Safari

[ghost]

As you can see, it looks like that the font weight of the text in this page was decreased implicitly during the ripple animation. Some of the demos in element catalog that contains paper-ripple could also find this issue.

However this weird behavior appears differently with paper-toast, the font weight won't restored to the original value until the toast disappear.

Other demo pages that could find this issue:

• paper-ripple
• paper-badge
• paper-radio-button

I'm using Safari 9.1 on OS X 10.11.4.