Assuming you are talking about blockchain.info, not the blockchain itself.  Blockchain.info is just one part of the network, it shows when it sees the block which is not instant it is mined.  It appears 303836-303840 were all generated within a very small window and so the order that they were generated and consequently built upon was not the same order that blockchain.info saw them.

It could very well be this http://money.cnn.com/2013/11/04/technology/bitcoin-flaw/ there has been a well known flaw in the bitcoin protocol which would have to be exploited with a lot of hash power close to 50% but even 35 or 40% could pull it off pretty easily through the getwork protocol. It is done by when a block is solved by pool they keep it secret and not broadcast to the network that a block has been found giving  whoever found the block a head start on everybody on the next block while everybody else is working on  a empty block that can't be found and has already been found. Ghash definitely has the hash power to pull it off that other I.P addy could just be a unpublicized address for ghash how  would we know?. I've noticed quite a few times right after ghash solves a block a unknown I.p quickly solves a block right after as well as conflicting times of back to back blocks solved by ghash? This is of course speculation but with the amount of blocks Ghash solves it is very well in the realm of possibilities........

A bug?

I see you are very emotional..
sorry "sweety"  but there was no hysterism or panic on my sentence.. just a question

ask a question <------> Panic!!!!

Ok I got it now. Sorry!

It is normal in Bitcoin for this to occur

It says image unavailable, can anyone provide an imgur link or another direct link?