Read failure when adding node + move; Or: What is the right way to add a node?

[David Boxenhorn <da...@citypath.com>]

Initial state: 3 nodes, RF=3, version = 0.7.8, some queries are with
CL=QUORUM

1. Add node with with correct token for 4 nodes, repair
2. Move first node to balance 4 nodes, repair
3. Move second node

===> Start getting timeouts, Hector warning: WARNING - Error:
me.prettyprint.hector.api.exceptions.HUnavailableException: : May not be
enough replicas present to handle consistency level.

What is going on? My traffic isn't high. None of my nodes' logs show
ANYTHING during the move

4. When the node finishes moving, the timeouts stop happening

Is there some state in the above scenario that I don't have the required
replication of at least 2?