I saw that overnight.. seemed like something more than just fast blocks occured. My pool has solved back to back to back to back blocks, some within 1 second of eachother (most about 20 seconds apart) over the past few days and difficulty never did this. It jumped, but not like that. Could be wrong, but it sure seemed odd.
Not to mention the odds of finding that many blocks all within 180 seconds. I've been watching the nethashrate bobble the last couple of days, and it would take more than a multipool to do that.
Well, things seem back on track.
Average Block time is 40 seconds. 1 second block times are certainly possible, albeit unlikely that several would occur in a row. But certainly possible.
The fact that they were confirmed should be enough to chalk it up to odd coincidence. If somebody was messing with the chain and attempting to cause harm we wouldn't know about it until the chain was actually forked. We would all just continue on the wrong chain unknowingly. Since the blocks did confirm and have not been orphaned after they were confirmed (sure sign of something amiss...) then I think its safe to assume things are running fine.