As an intervention, stop running Blink's rendering pipeline (including requestAnimationFrame callbacks) for content which isn't visible in the viewport. This helps to avoid doing unnecessary work for animations which aren't going to be seen by the user.
Docs: https://docs.google.com/document/d/1Dd4qi1b_iX-OCZpelvXxizjq6dDJ76XNtk37SZEoTYQ/edit