This assumes that the coin turned in the holder and was not already toned at the time of grading, and that the toning has detrimentally affected the reflectivity of the fields. To me, the toning is pretty minor and shouldn't really affect the grade that much.
Looking at the slab shot, that coin has a nice black and white contrast. I dont think it qualifies as a bugs bunny. Athough i wouldnt be surprised if there isnt a clashed proof floating around out there in the wild somewheres
I wish there was a clash in the field but, I can't find one. There is a nice rainbow through liberty, I agree it hasn't affected the contrast. @chascat the edge toning reminds me of it sitting in an album before grading. I am sure it has turned some, since being in the slab.
You may be right...it's also common for that vintage ANACS slab to produce that brown edge toning, then spread to the rest of the surface...I've had several do just that while I've owned them, some tone quite rapidly which is usually a shock to discover. I had a 1917 dime start out totally brilliant and then tone a nice multicolored bullseye...I was bummed at first noticing the toning, but after a while, the colors appeared and I loved the coin again. On the other hand, I've some Morgans which developed ugly dark toning which I now hate. There's some chemical in the labels of the soap bar slabs which may cause this reaction. It may also be in the storage method?