Block orphaned by same miner? Just noticed 2 conflicting blocks by the same pool.

One of the blocks was naturally orphaned, but why would the same pool broadcast 2 such blocks? Does it happen often?
Well that is simply bad luck. It can happen if the miner uses multiple Bitcoin nodes to handle the getwork or stratum requests. In the case of GHash.io my guess is that they either have so many resources that a single nodes cannot handle all the work to keep them working, so they created multiple nodes and distributed the resources on them.

Another reason might be that they have multiple locations, and in order to keep latency low, they have local nodes feeding work to the resources. This scenario would fit pools like btcguild.

While certainly annoying, it is not really anything you can do against it, if they'd known from the other block from their own network they would simply have dropped it and we wouldn't have known about it.