Version: 28.0.1469.0 (Official Build 192780) dev but it's been happening for a while now
OS: Mac OS X
What steps will reproduce the problem?
1. Load HTML spec (http://whatwg.org/C)
2. Leave it loaded for a long time while using the browser
3. Scroll down half-way and look for serif text
You're not supposed to see any serif. But you do.
The text that turns serif still leaves room for its proper font.
Sometimes I see this on other pages too, not just the HTML spec.
I was assuming other people would see this too, but the fact that this is still broken suggests to me it only happens if you have really large files open?