What happened with network right about just now? Few client crashes, mined like 20 blocks per minute and then back to normal (mentioned blocks removed)
If a difficult block takes a while to be solved then the difficulty algorithm adjusts for the following blocks to ensure that there are close to 675 blocks per day. Do let's say a block hasn't been solved in an hour since the previous block, as soon as it is solved the chain will lower the difficulty to catch up on the blocks that should have been issued in that last hour.