I hiked/climbed the Mt Whitney Mountaineers' Route last Friday and was warned by a rep in the USFS Visitor Center of a recent rock fall and that the MR had been changed.
A couple of returning hikers also warned me of this. One said that the rock fall made moving up the scree easier.
Here is what I encountered just above and to the right of the notch. This is the first time I had gone up the MR. Was that big rock blocking the route there before?

I found that there were many places where the rocks were very unstable. A lot were tumbling down the chute.
I had to turn around due to an impending thunderstorm.