Yeap, that's the wormhole. It's kinda like KGW, but locksdown quicker to prevent blocks from being instasolved when a high hash rental miner or multipool latches on to it. The night (BOB) was listed on bittrex.com such an event happened and difficulty jumped from 4 to 500 in two blocks, but when it didn't turn into a coin fountain, the miner went away and it takes a block or two to readjust to the hashrate from before the event.  Depending on the difficulty it was forced to rise to, and the hash left afterward.. the blocks will take some additional time to solve. In this cast, it took 15 hours.  Everythings hunkee-dory now tho.