Indy RHS head failure

With the 1.6 ratio rockers, the actual lift would be more like .575 and .580.

If the failed valve and the about-to-fail valve are both intakes, then that gives a bit more credence to the idea of valve float. The intakes are heavier and would tend to float just a bit sooner than the exhausts. (Of course, the pushrod and lifter weight would be the same for both.)