Minimal repro: http://jsfiddle.net/6z9ujy6p/1/ Every time the font-size changes in one of the h2 children, 8px of height gets added to the li.
Confirmed in OSX Safari 9.1 (11601.5.17.1)
Safari, Chrome, and Firefox all agree on rendering for this test case. I don't believe there is any remaining compatibility issue.