Scroll down the page by pressing the 'down' arrow over and over. You will note how the current page rendering repeatedly doubles in vertical length and then snaps back to the correct rendering. It's really terrible to try to read pages that have this problem.
I see this on OS X on nightly, by the way. It's been going on for a while, too (on the order of weeks, probably?).
Josh, is this happening on any page or specific ones? Does it happen when e10s is disabled? What version of OSX? Is it on local screen or external monitor? Also, do you have add-ons running? If so, can this be reproduced with them disabled (or in a fresh profile)?
Is this a dup of bug 1192918?
(In reply to Lee Salzman [:eihrul] from comment #3) > Is this a dup of bug 1192918? yes. duping.