[Wavery]

It appears to me like the tire that is causing the wheel well damage is starting to come apart.

The reason that I say that is because you are experiencing contact with the front of the wheel well as well as the top. The only way that can happen (other than the complete axle moving aft) is if the tire is actually expanding at highway speed. This can be caused by excessive speed (centrifugal force) or tire tread separation.