Re: [850 TH] Slush's Pool (mining.bitcoin.cz); TX FEES + VarDiff
AND the last one was just found to be invalid.
24 seconds too late, apparently. Nothing in the pipe. 
So a different pool or someone found the block 24 seconds before us?
Or, better, some pool has found a block. Because their block is different from the one our pool has found.
They've found a block with the same block number ("height"), i.e. position in the block chain.