It works on Safari on Mac. Repro: 1) Go to amazon.com 2) On right hand side, search in A9 for any term 3) The <span> that's overlayed is not rendered 4) It looks like the code has special CSS for user agent Safari. This works for safari on Mac.
This appears fixed with my local build of r24148
Matt, do you suspect some particular commit? It's a bit strange when a bug fixes itself in a few hours - maybe there is some difference in configuration.