I've looked at your user profile to suggest you're a troll account. Please elaborate on the observations you have that led to this conclusion.

Let's not revert to ad hominems so quickly. If you looked through my submissions, you'll see that I explained the problem elsewhere. Here it is again:

Imagine two nodes, both initiating updates to the same row. One has observed a number of node additions and deletions. The other has not. They will perform their updates on disjoint sets.

Additions to the ring are not atomic, therefore quorums aren't.